• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.1
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• pp.97-109
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• 2015

In this paper, we design and implement a two-way automatic communication system using a mobile instant messenger that can provide a customized service through a real-time two-way communication using a mobile instant messaging service. Two-way automatic communication system using a mobile instant messenger can improve the quality and quantity of information in real-time update of the information through the feedback. In addition, since it is communicated by using a mobile Instant Messanger in 1:1 there is no concerns that is recognized as spam, as well as it is possible to provide customized information for each user. Two-way automatic communication system using a mobile instant messanger shows the difference of the speed according to the data input time in typing by hands in result of comparing the time to input a date and the processing speed to search a data. Therefore in category treatment, command processing and natural language processing, Category treatment way is the most excellent in aspect of data processing speed, otherwise in aspect of the total speed to combine the data input time and the processing time, the command processing way is the best method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.9
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• pp.2081-2100
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• 2013

In this paper, we propose a cooperative hybrid spectrum sharing protocol by jointly considering interweave (opportunistic) and underlay schemes. In the proposed protocol, secondary users can access the licensed spectrum along with the primary system. Our network scenario comprises a single primary transmitter-receiver (PTx-PRx) pair and a group of M secondary transmitter-receiver (STx-SRx) pairs within the transmission range of the primary system. Secondary transmitters are divided into two groups: active and inactive. A secondary transmitter that gets an opportunity to access the secondary spectrum is called "active". One of the idle or inactive secondary transmitters that achieves the primary request target rate $R_{PT}$ will be selected as a best decode-and-forward (DF) relay (Re) to forward the primary information when the data rate of the direct link between PTx and PRx falls below $R_{PT}$. We investigate the ergodic capacity and outage probability of the primary system with cooperative relaying and outage probability of the secondary system. Our theoretical and simulation results show that both the primary and secondary systems are able to achieve performance improvement in terms of outage probability. It is also shown that ergodic capacity and outage probability improve when the active secondary transmitter is located farther away from the PRx.

• Journal of Ocean Engineering and Technology
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• v.24 no.3
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• pp.64-71
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• 2010

This paper summarizes the development of an ART control system panel with a touch screen and sensors to measure the roll and roll rate of ships. The control system hardware consists of two micro-processors, analog and digital I/O circuits, various relay circuits, etc. Sensor fusion and moving cross algorithms are implemented to accurately estimate the roll angle and roll period. In addition, the control system adopts a fault detection algorithm to inform users of ART system faults. A touch screen in the control panel can display the ART system states and faults. The performance of the developed system was verified on real sea trials.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.59-71
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• 2002

Korean government, port and logistics companies have given a lot of their efforts to exchange electronic documents between themselves and their partners. As the results of them, Korean EDI(Electronic Data Interchange) standards were made by Korean EDIFACT committee and the standards have been used by companies and governmental organizations in Korea. However, Korean port and logistics EDI system is based on YAN(Value Added Network) and one VAN company has monopolistic right to relay EDI documents to Korean HOMAF(Ministry of Maritime Affairs & Fisheries) and Customs Service. Therefore it leads to a lot of problems such as inconvenient software, expensive transmission fee, insufficient improvement of business process and the difficulty of connection with the in-house systems of user companies. For solving these problems, this study is aimed to progress for XML and XML-based electronic commerce framework. This paper shows a optimal XML/EDl method using XML/EDl, BizTalk Framework, ebXML Framework. Fer improving extant problems in port and logistics industry, this paper proposed XML/EDl system based on system architectural level, support technical level, business infrastructure level.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.16-33
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• 2019

In this paper, a full-duplex NOMA relaying based underlay device-to-device (D2D) communication scheme is proposed, in which D2D transmitter assists cellular downlink transmission as a full-duplex relay. Specifically, D2D transmitter receives signals from base station and transmits the superposition signals to D2D receiver and cellular user in NOMA scheme simultaneously. Furthermore, we investigate the power allocation under the proposed scheme, aiming to maximize D2D link's achievable transmit rate under cellular link's transmit rate constraint and total power constraint. To tackle the power allocation problem, we first propose a power allocation method based on linear fractional programming. In addition, we derive closed-form expressions of the optimal transmit power for base station and D2D transmitter. Simulation results show that the performance of two solutions matches well and the proposed full-duplex NOMA relaying based underlay D2D communication scheme outperforms existing full-duplex relaying based D2D communication scheme.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.45-49
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• 2001

Korean government and companies have given a lot of their efforts to exchange electronic documents between themselves and their partners. As the results of them. Korean EDI standards were made by Korean EDIFACT Committee and the standards have been used by companies and governmental organization in Korea. However, Korean export customs clearance EDI system is based on VAN(Value Added Network) and one VAN company ha monopolistic right to relay EDI documents to Korean Customs Service. Therefor is leads to a lot of problems such as inconvenient software, expensive transmission fee and the difficulty of connection with the in-house systems of user companies. To solve these problems, a few good solutions and systems have been suggested and one of them is the Internet EDI. we will suggest a new export customs clearance EDI system running on the Web. This system is basically an Internet EDI system, but we have developed this system using XML instead of HTML, XML is a new markup language with merit such as isolating data from style of documents. This system consists of 7 modules, schema/style/template management, XML/EDI document management, XML/EDI transformation, EDI transmission, certification management and log management. Also this system can be used with other traditional EDI systems that have UN/EDIFACT standards. We will discuss the advantages and disadvantages of XML/EDI system for customs clearance. The development of this system will be a leading study for XML/EDI standards in export clearance EDI system.

• ETRI Journal
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• v.45 no.2
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• pp.254-266
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• 2023

This paper investigates the effect of hardware impairments (HIs) and imperfect channel state information (ICSI) on a SWIPT-assisted adaptive nonorthogonal multiple access (NOMA)/orthogonal multiple access (OMA) system over independent and nonidentical Rayleigh fading channels. In the NOMA mode, the energy-constrained near users act as a relay to improve the performance for the far users. The OMA transmission mode is adopted to avoid a complete outage when NOMA is infeasible. The best user selection scheme is considered to maximize the energy harvested and avoid error propagation. To characterize the performance of the proposed systems, closed-form and asymptotic expressions of the outage probability for both near and far users are studied. Moreover, exact and approximate expressions of the ergodic rate for near and far users are investigated. Simulation results are provided to verify our theoretical analysis and confirm the superiority of the proposed NOMA/OMA scheme in comparison with the conventional NOMA and OMA protocol with/without HIs and ICSI.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.271-280
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• 2014

In wireless sensor networks, there have been two methods for sensing continuously moving object tracking: user-query based method and periodic report based method. Although the former method requires overhead for user query rather than the latter method, the former one is known as an energy-efficient method without transferring unnecessary information. In the former method, a virtual tree, consisting of sensor nodes, is exploited for the user querying and sensor reporting. The tree stores the information about mobile objects; the stored information is triggered to report by the user query. However, in case of fast moving object, the tracking accuracy reduces due to the time delay of end-to-end repeated query. To solve the problem, we propose a query relaying method reducing the time delay for mobile object tracking. In the proposed method, the nodes in the tree relay the query to the adjacent node according to the movement of mobile object tracking. Relaying the query message reduces the end-to-end querying time delay. Simulation results show that our method is superior to the existing ones in terms of tracking accuracy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.7-16
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• 2020

The mobile electronic notification service delivers notifications through mobile phone text or app-based message push to solve various problems of the paper-based mail service. And it is a service that an electronic document relay company proves to prove delivery. In order for public and administrative agencies to provide mobile electronic notification service, the user's identification information of the mobile phone number or the subscribed app is required. To overcome these limitations, ICT-regulated sandbox system was used to allow collective conversion of users' resident registration numbers into connecting information (CI). Therefore, in this paper, we propose a technical method for safe management of user CI in mobile electronic notice service, identity verification of electronic notice readers, and prevention of forgery and forgery of electronic notices. Through the proposed method, it is confirmed that the service can be activated by minimizing the adverse function of the mobile electronic notification service by securing the user's convenience and technical safety for the CI.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.85-94
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• 1998

Due to relatively high permittivity of water in soils, we placed the soil condenser into soils to measure the soil moisture content. The soil condenser was made with two insulated iron sticks. The capacitance of the soil condenser was determined by the pulse period from RC type oscillation circuit and the highest voltage output accepting 10MHz pulse. After zero point adjustment, the measured relative capacitance percentage (RCS) to the standard condenser obtained by the oscillation circuit almost linearly correlated with the end depth of the sensor submerged in water. The RC type oscillation was disturbed by many sensor installed in a close distance in one place, presumably resulting in that the sensor sticks played as a interfering antennas generating or accepting electron waves from them. The temperature dependance of the output from the sensors could be corrected through experimentally determined revision function. Although lineal correlation was found between soil moisture and RCS, users should derive their own correlation function for every sensor to measure soil moisture, because the outputs were influenced by the installation depth and layout in the soil. The voltage type sensor responded inversely with soil moisture content and so was not suitable to the accurate measurement of soil moisture, but allows high economic benefit in various application such as simplified measurement of soil moisture and irrigation line control because of its low component count. The voltage type moisture sensor could be reinforced by relay controlling circuit to open and to close the solenoid valves respectively at optimal limits of the least and the most soil moisture according to user's adjustment.