• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.693-699
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• 2013

In this paper, ${\pi}/4$-DQPSK modem according to ITU-R M.1842-1 recommendation Annex1 is investigated and simulated. At first, standardization and technical trend of VHF maritime mobile communication are introduced. The ${\pi}/4$-DQPSK modem defined in the Annex1 should support 28.8Kbps bit transmission rate within 25KHz frequency bandwidth. We describe the system model and simulation process of ${\pi}/4$-DQPSK modem transmitter and receiver design with RRC(Root Raised Cosine) transmitter and receiver filter. Then we suggest various graphical simulation results(time domain signals, constellation, power spectral density according to roll-off factor, eye diagram), and show simulated BER performance of the modem. From the simulation results, it is shown that roll-off factor of RRC filter affects to BER performance according to SNR and the designed simulation model meets the spectrum mask requirement suggested in ITU-R M.1842-1 recommendation.

• Journal of Distribution Science
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• v.14 no.4
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• pp.5-11
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• 2016

Purpose - The Education Ministry has plans to select top 10 percent academic journals among the domestic registration journals in NRF(National Research Foundation of Korea), and designate them as outstanding academic journals. To reflect this trend, KODISA has set its sights on paper publication rate and citation index with pushing forward globalism. First, this study will arrange the process of globalism and the current state of paper submission, and propose the direction of improvement in academic journals through understanding the characteristics of each major field. Research design, data, and methodology - KODISA has preceeded in examining and publishing research papers related to distribution field through indirectly or stimulating academic advancement. KODISA covers the whole fields in social science as well as in business administration and economics that associated with distribution field not limiting only within the range of distribution field. That is, the new subject that contributes to the progress in distribution field with original research can be a priority criteria in KODISA journal publication. Results - The major fields in papers published in KODISA can be categorized broadly as distribution field with economic and business administration point of view. Therefore, the distribution field with economic point of view includes the issues such as regulations, system, industry, market environment, distribution system, trade, and macroeconomics, etc. The business administration point of view in distribution includes distribution strategy, distribution organization, and distribution channel from the perspectives of the firm, etc. Conclusions - The aim of KODISA in 2020 is to be a global academic journal as SCI level of each journal in KODISA, JDS(Registration journal), IJIDB(Registration candidate), EAJBM(Registration candidate), JAFEB(Cabell's Registration journal). The KODISA journals have already settled as the largest academic society and journals of Korea in 2016 currently from humanities and social sciences area by the most gross in publication circulation, volumes, and types. Hereafter, KODISA will focus on the improvement for the objective indicators such as Impact Factor and Centrality index as qualitative growth as well as quantitative expansion. By doing so, KODISA will be a forum for developmental academic debate with attracting the world's greatest scholars' papers. Furthermore, they will be recognized journals and grow as the first-rate academic journals inside and outside of Korea.

• The Journal of Industrial Distribution & Business
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• v.9 no.1
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• pp.67-76
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• 2018

Purpose - With the worldwide aging problem and the development of globalization, customers prefer to seek affordable medical services with the higher quality overseas. This new trend has urged some destination countries to improve their services for the more competitive advantages over other countries. Literature research indicate that medical quality and cost may be the key factors influencing global patients' decisions. In the international environment, however, medical tourism destinations are selected due to cultural similarity between the hosting country and the customers' own country. The more similarity perceived between the two countries leads foreign patients to choose the considering country as the destination for medical tourism. However, little research has been conducted on this topic. Thus, we empirically investigate how cultural similarity influences Chinese medical customers' choice of the destinations. We also consider the factors related to medical competency and travel attribute which might affect customers' decisions along with some moderating roles of disease types. Research design, data, and methodology - We proposed a research model in order to confirm the relations among different variables of cultural similarity, medical competency, travel attractiveness, disease types, and destination choice. The questionnaire survey is processed in the more economically developed regions of China such as Beijing, Shanghai, and Jiangsu. Conditional logit regression is applied to analyze the data of 881. Results - Results indicate that cultural similarity is the important predictor of Chinese customers' decision to select a medical country. However, the effects of cultural similarity vary according to the disease types. We also find that medical competency and travel attractiveness influence their decisions with the moderating role of disease types. Conclusions - Cultural similarity is the important factor that influences Chinese potential medical tourists' decisions to select a destination. Marketing managers should consider the effects of cultural similarity when developing strategies for attracting Chinese medical tourists. Since medical competency and travel attractiveness are still the critical key elements for them to evaluate the destination countries, it is necessary to continuously improve medical service quality and facilities. The results also recommend that medical managers should sharpen their marketing strategies by segmenting Chinese potential customers in terms of disease types.

• Women's Health Nursing
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• v.24 no.1
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• pp.90-103
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• 2018

Purpose: To analyze articles published in the Korean Journal of Women Health Nursing from 2013 to 2017 to determine the latest research trends and understand how 2013 Korea Women's Health Statistics were reflected in journal articles. Methods: A total of 130 studies were analyzed. Research design, types of research, research framework, research subjects, characteristics of quantitative research, characteristics of qualitative research, and keywords were analyzed using a structured analysis format. Results: Quantitative and qualitative research accounted for 83.8% and 13% of these 130 studies analyzed, respectively. Non-experimental and experimental research accounted for 70.7% and 13.1% of these studies, respectively. The most frequent study subjects were childbearing women (62.8%), including college students, mothers, and adults. A total of 69.1% of non-experimental research and 88.2% of experimental research used convenience sampling. Questionnaires were most frequently used for data collection. The most frequent keyword domain involved health-related concepts (41%) among nine domains and the most frequently used keyword was "women." Conclusion: This study suggest that further experimental research should be conducted in the future. Also, adolescent and the elderly women should be focused on as subjects in future studies based on results of 2013 Korean Women's Health Statistics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2119-2124
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• 2008

An information-oriented basis in today's society has been changing fast, and the desire for connectivity has caused an exponential growth in wireless communication and sensor network. Sensor networks using RFID, in particular, have led this trend due to the increasing exchange of data in Ubiquitous such as the home RF, access control system, U-Healthcare, and Logistics information Systems. Also, the RFID when it applies a technique, is able to raise the stability of shipping as controling the mobile course and an entrance and exit of the crews an well as previously preventing an accident from shipping. In this paper, we designed and implemented personnel control system using UHF-RFID in vessels which shows through host PC reading and writing tag.

• Korean Journal of Remote Sensing
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• v.26 no.2
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• pp.99-108
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• 2010

According to the recent trend on advancement of web computing technologies and diversification of spatial data types to be processed, designing and implementing of web-based applications using open sources has been regarded as one of important users-needs. In this study, a kind of geo-browser model composed of client-middleware-DBMS stack is suggested, and the prototype implementation are performed. Especially, modularization of user interfaces is contributed to increase both applicability for a certain target system and accessibility for web users. In middleware, it has functions to decrease erroneous factors on spatial data registration processes, and provides spatial data the form of OGC WxS standards. It is thought that this system is helpful to utilize as basic architecture and the related implementation model for web-based geo-spatial services and their applications.

• Steel and Composite Structures
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• v.33 no.4
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• pp.615-627
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• 2019

This paper aims to study the compressive behavior of circular hollow and concrete-filled steel tubular stub columns under simulated marine atmospheric corrosion. The specimens after salt spray corrosion were tested under axial compressive load. Steel grade and corrosion level were mainly considered in the study. The mechanical behavior of circular CFST specimens is compared with that of the corresponding hollow ones. Design methods for circular hollow and concrete-filled steel tubular stub columns are modified to consider the effect of marine atmospheric corrosion. The results show that linear fitting curves could be used to present the relationship between corrosion rate and the mechanical properties of steel after simulated marine atmospheric corrosion. The ultimate strength of hollow steel tubular and CFST columns decrease with the increase of corrosion rate while the ultimate displacement of those are hardly affected by corrosion rate. Increasing corrosion rate would change the failure of CFST stub column from ductile failure to brittle failure. Corrosion rate would decrease the ductility indexes of CFST columns, rather than those of hollow steel tubular columns. The confinement factor ${\xi}$ of CFST columns decreases with the increase of corrosion rate while the ratio between test value and nominal value shows an opposite trend. With considering marine atmospheric corrosion, the predicted axial strength of hollow steel tubular and CFST columns by Chinese standard agree well with the tested values while the predictions by Japanese standard seem conservative.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.5
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• pp.329-339
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• 2019

Recently, the advancement of information and communication technology(ICT) is expanding the connectivity through Internet of Things(IoT), and the media of connection is also expanding from wire/cable transmission to broadband wireless communication, which has significantly improved mobility. This hyperconnectivity has become a key element of the fourth industrial revolution, whereas the supervisory control network of purification plants in korea is operated as a communication network separated from the outside, thereby lagging in terms of connectivity. This is considered the best way to ensure security, and thus there is hardly any consideration of establishing alternatives to operate an efficient and stable communication network. Moreover, security for management of a commercialized communication network and network management solution may be accompanied by immense costs, making it more difficult to make new attempts. Therefore, to improve the conditions for the current supervisory control network of purification plants, this study developed a industrial security L2 switch that supports modbus TCP(Transmission Control Protocol) communication and encryption function of the transmission section. As a result, the communication security performance improved significantly, and the cost for implementing the network management system using Historical Trend and information of HMI(Human Machine Interface) could be reduced by approximately KRW 200 million. The results of this study may be applied to systems for gas, electricity and social safety nets that are infrastructure communication networks that are similar to purification plants.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.187-194
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• 2008

Because the types and severities of most engine faults are various and complex, it is not easy that the conventional model based fault detection approach like the GPA(Gas Path Analysis) method can monitor all engine fault conditions. Therefore this study proposed newly a diagnostic algorithm for isolating and diagnosing effectively the faulted components of the smart UAV propulsion system, which has been developed by KARI(Korea Aerospace Research Institute), using the fuzzy logic and the neural network algorithms. A precise performance model should be needed to perform the model-based diagnostics. The based engine performance model was developed using SIMULINK. For the work and mass flow matching between components of the steady-state simulation, the state-flow library was applied. The proposed steady-state performance model can simulate off-design point performance at various flight conditions and part loads, and in order to evaluate the steady-state performance model their simulation results were compared with manufacturer's performance deck data. According to comparison results, it was confirm that the steady-state model well agreed with the deck data within 3% in all flight envelop. The diagnosis procedure of the proposed diagnostic system has the following steps. Firstly after obtaining database of fault patterns through performance simulation, then secondly the diagnostic system was trained by the FFBP networks. Thirdly after analyzing the trend of the measuring parameters due to fault patterns, then fourthly faulted components were isolated using the fuzzy logic. Finally magnitudes of the detected faults were obtained by the trained neural networks. Because the detected faults have almost same as degradation values of the implanted fault pattern, it was confirmed that the proposed diagnostic system can detect well the engine faults.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.439-444
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• 2011

Doosan Heavy Industries & Construction Co., Ltd. has been recently developing the gas turbine engine using the biogas as fuel. This paper describes the non-reacting and reacting flow analysis of the combustor which is one of the main components in gas turbine engine. Through CFD analysis, investigation has been performed to evaluate the primary factors for aerodynamic design and to predict combustor behaviors during operation with various fuel distribution ratios. The calculation results are compared with rig test data, which reveals that CFD predictions such as pressure loss, air distribution ratio, and recirculation flow are quite reliable. The trend of NO formation was similar with the test, except the low fuel distribution ratio.