• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.9
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• pp.4390-4407
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• 2019

The paucity of pilot signals in Massive MIMO system is a vital issue. To accommodate substantial number of users, pilot signals are reused. This leads to interference, resulting in pilot contamination and degrades channel estimation at the Base Station (BS). Hence, mitigation of pilot contamination is exigency in Massive MIMO system. The proposed Time Shifted Pilot Signal Transmission with Pilot signal Hopping (TSPTPH), addresses the pilot contamination issue by transmitting pilot signals in non-overlapping time interval with hopping of pilot signals in each transmission slot. Hopping is carried by switching user to new a pilot signal in each transmission slot, resulting in random change of interfering users. This contributes to the change in channel coefficient, which leads to improved channel estimation at the BS and therefore enhances the efficiency of Massive MIMO system. In this system, Uplink Signal Power to Interference plus Noise Power Ratio (SINR) and data-rate are calculated for pilot signal reuse factor 1 and 3, by estimating the channel with Least Square estimation. The proposed system also reduces the uplink Signal power for data transmission of each User Equipment for normalized spectral efficiency with rising number of antennas at the BS and thus improves battery life.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.1-9
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• 2009

Relay-assisted multiple input technique has become a promising candidate for next generation broadband wireless communications. In this paper, we propose channel selective relay-based multiple input transmission system. In the proposed system, single carrier frequency division multiple access (SC-FDMA) and orthogonal frequency division multiple access (OFDMA) are adopted for uplink and downlink transmissions, respectively. The performance of relay-based system can be improved by using the subcarriers selectively based on the channel condition between relay station (RS) and mobile station, or between RS and base station. Simulation results show that the proposed relay-based system considerably outperforms the conventional relay-based system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.119-120
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• 2012

The International Hydrographic Organization (IHO) developed S-100 standards as a framework for a variety of data and service for hydrography and a standard research is in process, including a next-generation electronic chart standard, for products and services based on this.The need for standard storage and utilization of navigation routes generated by ECDIS and navigation system using navigation planning features has emerged and a standard research based on S-100 standard has been performed. Route information standard is needed for interoperability among route information generated by a variety of navigation system and requires an examination for the possibility of applicability. In this research, route generation tools and standard-based generation and result of route information using these tools in order to examine the application of route information standards have been executed.In details, first, as a module capable of generating route information, a module that can store values in memory based on route information standards of S-100, second, a module that can store route information in the memory in XML form, third, it includes loading module for route information stored as XML.In this research, we verified normal generation of route information, storage of generated route information and loading functions through developing three modules.

• Journal of Digital Convergence
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• v.10 no.5
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• pp.223-232
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• 2012

Recently, the leakage of personal information and privacy piracy increase. The victimized case of the malicious object rapidlies increase. Most of users use the windows operating system. Recently, the Windows 7 operating system was announced. Therefore, we need to study for the intrusion response technique at the next generation operate system circumstances. The accident response technique developed till now was mostly implemented around the Windows XP or the Windows Vista. However, a new vulnerability problem will be happen in the breach process of reaction as the Windows 7 operating system is announced. In the windows operating system, the system incident event needs to be efficiently analyzed. For this, the event information generated in a system needs to be visually analyzed around the time information or the security threat weight information. Therefore, in this research, we analyzed visually about the system event information generated in the Windows 7 operating system. And the system analyzing the system incident through the visual event information analysis process was designed and implemented. In case of using the system developed in this study the more efficient accident analysis is expected to be possible.

• KIISE Transactions on Computing Practices
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• v.21 no.6
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• pp.430-435
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• 2015

IP-based, next generation digital broadcast systems transmit DASH segment files. Designed by the DASH system, DASH segment files provide variable quality of contents, while the size of DASH segment files varies even if the file has the same quality. Delays and inefficient use of resources are major challenges in the transmission of variable size DASH segment files in broadcasting systems. Traditional broadcasting transmission systems are designed according to characteristics of physical layer of broadcast, and thus, delay and inefficient resources use is difficult to find. Yet, transmission content quantities continue to rise in the next-generation broadcasting systems (e.g. FHD, UHD (4k, 8k)) with variability of the segments file size as well. Resources for next-generation broadcast are more abundant than traditional broadcast with recent development, but continue to be limited and fixed. Resource delay and inefficiency are important but has not been extensively studied. We propose a transmission structure solution to analyze the delay and efficiency of the resource as each DASH segment file is transmitted, and have further performed simulation studies.

• Journal of Korean Library and Information Science Society
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• v.37 no.3
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• pp.415-431
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• 2006

The semantic web was proposed as the next generation web technology. In the environment of the semantic web, resources as well defined and related with each other semantically, the RDF supports this basic mechanism. To establish and develop the semantic web. the basic technologies related to RDF data must be pre-established. In this research, we develop methods for storing and querying RDF data using an XML database system. As using XML database, XML data and RDF data can be integrated and efficiently managed. We construct and evaluate a system applying the proposed method to store and search data, we compared the query processing performance on our system with that of an existing system. The experiment result show that our system processes queries more efficiently.

• Transactions of the Society of Information Storage Systems
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• v.3 no.1
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• pp.1-4
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• 2007

A high density optical data storage device has been required for many years. In the field of the optical data storage, a near-field recording (NFR) technology is considered as a next generation one for achieving the high data density. Due to an evanescent wave effect occurred under 100nm distance which is the excessively small distance between the SIL and the disc, the most significant and difficult problem in this technology is to maintain a gap between a solid immersion lens (SIL) and a disc. Also, maintaining the gap under at least 50nm is required in the NFR gap servo system to use the evanescent wave effect efficiently. There are some institutes that have shown the novel gap servo control. In general, they use a mode switching servo method which consists of approach, hand-over and gap control mode. However there is a critical problem such as an overshoot at the tuning point from the approach mode to the hand-over mode, which may cause a collision between the SIL and the disc. In this paper, we show our NFR system and an improved gap servo system using an exponential function as the approach mode which can reduce the overshoot.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.299-305
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• 2016

It is require to design the next generation avionics system while considering applicability under open architecture where standerd communication module is used. In this situation, if the existing schemes cannot guarantee new requirement, new system development is demanded. In this paper, we present design, implementation, and testing procedure for message based middleware to support operational flight program on avionics. System architecture include mission computer (MC) and large area display (LAD) over standard socket communication based on reliable Ethernet. Finally, experimental results demonstrate that the proposed middleware can guarantee real-time with 20msec as well as reliability requirements with no lost packet.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.661-666
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• 2002

We need the flexible method for communication network configuration and fault management business procedure. Therefore development of systematic integrating fault management system is essential to meet on these requests. We must design the integrating fault management system so that can run the repair processing for both data communication network management and new next generation data communication network of various type. In general it is effective that the system is consisted of decentralized module to be accessibele for business logic and datum to remote area. To Solve these problem, a method is to use object-oriented design technique. That is, it is to abstract reusability objects and make component module using the abstracted objects. In this paper, we propose a fault management system of communication network service using object-oriented design techniques which are UML(Unified Modeling Language) and EJB(Enterprise Java Bean).

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.2
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• pp.25-31
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• 2019

As artificial intelligence technology has been developed rapidly, many researchers who are interested in next-generation vehicles have been studying on applying the artificial intelligence technology to advanced driver assistance systems (ADAS). In this paper, a method of applying deep learning algorithm to the lane departure warning system which is one of the main components of the ADAS was proposed. The performance of the proposed method was evaluated by taking a comparative experiments with the existing algorithm which is based on the line detection using image processing techniques. The experiments were carried out for two different driving situations with image databases for driving on a highway and on the urban streets. The experimental results showed that the proposed system has higher accuracy and precision than the existing method under both situations.