• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.149-156
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• 2014

Floor number determination has attracted considerable attention because many applications require accurate floor number information for providing better localization services in multistory buildings. This paper describes a Wi-Fi-based, low-complexity floor number determination method for multistory buildings. In our scheme, with the exception of floor ID and received signal strength of each WAP, detailed information on the wireless access point (WAP) coordinates is not needed. The multi-wall-floor model is used for the simulation and analysis. The simulation results show that the floor determination accuracy is nearly 100 given an adequate deployment density of WAPs on each floor. The results also show that the proposed method provides a good estimate of floor number even when only a few WAPs are implemented on each floor. Specifically, the proposed method can work under extreme conditions, i.e., where there are no WAPs on a floor.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.331-340
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• 2004

Deployment of an advanced on-line monitoring of the component integrity offers a prospect of improved performance, enhanced safety, and reduced overall cost for nuclear power plants. Ultrasonic guided waves have been known as one of the promising techniques that could be utilized for on-line monitoring. The present work is aimed at developing a new method for on-line monitoring of the pipes during the operation period of nuclear power plants. For this purpose, the steam generator (S/G) tube was selected as an object of tile experiment. Dispersion corves and the incident angles corresponding to the specific modes were calculated for the S/G tube. The modes of guided waves were identified by the time-frequency diagrams obtained by the short time Fourier transform. It was experimentally confirmed that there was no mode conversion when the ultrasonic guided waves passed over the curved region of the S/G tube. An optimum mode of guided wave for the S/G tube was suggested and verified by the experiment.

• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.129-142
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• 2014

Latest in Smart Grid projects are emerging as the biggest issue that smart meter should meet the security goal and the SW upgrade for compliance with future standard. However, unlike regular equipment, Smart meters should be designed in accordance with the regulation of legal metrology instrument in order to establish a fair trade-based business and unauthorized changes, it is not allowed and it is strictly limited by law. Therefore, this paper propose a new scheme of certification regarding type approval and verification for legal smart meter as analyzing the requirements of a smart meter regarding upgrade and security. This analysis shows that the proposed scheme comply with the regulation and the specification of smart meter by applying it to smart meter with smart card.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.5
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• pp.2103-2123
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• 2018

Ships built today are larger in scale and feature more complex structures. The ever-evolving systems used on board a ship require vast amounts of data processing. In the future, with the advent of smart ships, unmanned ships and other next-generation ships, the volumes of data to be processed will continue to increase. Yet, to date, ship data has been processed using wired networks. Placed at fixed locations, the nodes on wired networks often fail to process data from mobile devices. Despite many attempts made to use Wi-Fi on ships just as on land to create wireless networks, Wi-Fi has hardly been available due to the complex metal structures of ships. Therefore, Wi-Fi on ships has been patchy as the ship-wide total Wi-Fi coverage has not properly implemented. A new ship-wide wireless network environment is part of the technology conducive to the shipbuilding industry. The wireless network environment should not only serve the purpose of communication but also be able to manage and control multiple features in real-time: fault diagnostics, tracking, accident prevention and safety management. To better understand the characteristics of wireless frequencies for ships, this paper tests the widely used TETRA, UHF and Wi-Fi and sheds light on the features, advantages and disadvantages of each technology in ship settings. The proposed deployment of a Super Wi-Fi network leveraging the legacy UHF system of TMS generates a ship-wide wireless network environment. The experimental findings corroborate the feasibility of the proposed ship-wide Super Wi-Fi network environment.

• Journal of the Korean Society for Library and Information Science
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• v.22
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• pp.259-304
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• 1992

This paper examines 'Religion Class' in the scheme of the DDC. The major findings of the study are summerized as follows. 1. The first edition of DDC was published in 1876 in order to classify Amherst College Library collections. In spite of the continuous study and revision of the experts, the frameworks of the DDC systems are still kept unchanged. Only their subdivisions, reflecting those developments in the academic world, are developed and detailed more sophisticatedly. 2. The division of 200 does not function as generalities for all class of religion. Therefore, it is necessary to amend the division of 200 to serve generalities for all the religions of the world. 3. Standard subdivision for the christian religion and for the non-christian religion is different. So, the mnemonic nature has become weakened due to the dual standard subdivisions and the classification number becomes much longer and complicated. Therefore, one standard subdivision for all religions of the world is required. 4. Religion science was organized in late 19 C and developed continuously, but the DDC does not accomodate the religion science as a science. Accodingly, the DDC should be revised recognize religion science as a science not the christian science. 5. The deployment of classification scheme in Dewey's 200 is severely biased. That is to say, 9 division were assigned for christian religion, whereas only 1 division was assigned for non-christian religion. Therefore, an adjustment should be made to allocate subdivisions equally to all religions of the world. 6. General classification order of religion is prehistoric, primitive, ancient, modem and world religion in religion science. But, DDC does not accept this general classification order of religion, sticking to the biased expansion towards christianity. Therefore, DDC must adopt the general classification order of religion in the religion science. 7. Lastly, because of the limitation of decimal notation in DC, DDC does not accomodate new subject equally and classification number becomes longer. Therefore, centesimal expansion is proposed in order to make the classification number short, to enlarge its capacity of inclusion of new subject and to maintain consistency in the scheme.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.10
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• pp.679-690
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• 2013

Smartphones have features that users feel free to install/delete the program they want. Their emergence makes many developers rush into the Smartphone application development market. Thus, developing good applications quickly is becoming even more intense competition in the market. Because, however, the application development and deployment procedures are simple in the Android environments and anyone can participate in the development easily, applications not validated thoroughly are likely to be deployed. Therefore, a systematic approach that can verify Android-based applications with fewer burdens is required. In this paper, we propose a method that generates automatically GUI-based testing scenarios for the Android applications. The automated test scenario generation can reduce the time which the developer spends on testing, thus it can improve the productivity of the development in the testing phase.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.57-67
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• 2015

A large amount of work has been done in the areas of routing, MAC, QoS, capacity, location service, cooperative communication, fault tolerance, mobility models and various applications of mesh networks thanks to their merits of cost-effective way of deployment and flexibility in extending wireline services. Although multi-path routing protocols have been proposed to be used to provide QoS and fault-tolerance, there has not been any significant results discussed that support both in the literature to our best knowledge as they are often required in military and public safety applications. In this paper, we present a novel routing protocol for a mesh network based on the OFDM-TDMA collision-free MAC that discovers and maintains multiple paths that allows retransmitting and forwarding packets that have been blocked due to a link failure using an alternative next-hop node such that the delay-capacity tradeoff is reduced and the reliability is enhanced. Simulation results show that the proposed protocol performs well in terms of both the QoS and delivery ratio.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.34-50
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• 2012

This study set out to define a communication environment between an ITS center and field device required to be introduced in the nation in order to guarantee the interoperability, compatibility, and global competitiveness of communication between them in the nation. It also aimed to establish technical and policy plans for its introduction, develop an emulator for information exchange, and apply VMS by way of showing an example, thus testing its validity. First, a standard environment for information exchange between an ITS center and field device required to be introduced in the nation was defined as a dual protocol between DATEX and SNMP. The study also proposed a message definition system including meta-attribution definition and OID introduction. The study then suggested technical and policy plans for its introduction including securing enough feasibility with feedback through a model project of standard introduction, offering education and promotions for the standard in advance, providing methods to introduce and systematically manage OID, developing a hardware standard proper for the information exchange standard, and setting up an integrated management system to introduce a dual protocol.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.7
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• pp.10-14
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• 2015

Recently, the collection of the sensor data and its analysis become important as the smart buildings equipped with the various sensors appear as a usual scene. The interconnection through the wire cable among the sensors is indispensible because of the information collections such as the temperature, the humidity, and the luminance in the rooms and the hallways for the effective management of the in-building energies. However, these interconnections through the cabling will be very costly, time-consuming, and a difficult task since they will cause some damages to the buildings. Therefore, the interconnections through the unwired connections are required in terms of the deployment effectiveness such as time and cost In this paper, the design and the short sequence operation appropriateness are confirmed through the simulation of the signal measurement system for in-building propagation characteristics based on short signature sequence and the analysis of the system characteristics based on the false alarm probability is performed thereafter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.198-205
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• 2007

In ubiquitous environment a user can be provided with context-aware services based on his or her current location, time, and atmosphere. LBS(Location-Based Services) play an important role for ubiquitous context-aware computing. Because deployment and maintenance of this specialized equipment is costly, many studies have been conducted on positioning using only wireless equipment under a wireless LAN infrastructure. Because a CPS(Cooperative Positioning System) that uses the RSSI (Received Signal Strength Indicator) between mobile equipments is more accurate than beacon based positioning system, it requires great concentration in its applications. This study investigates the relationship between nodes by analyzing a WiPS (Wireless LAN indoor Positioning System), a similar type of CPS, and proposes a improved WiCOPS-d(Wireless Cooperative Positioning System using node density) to increase performance by determining the convergence adjustment factor based on node density.