• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.582-588
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• 2001

The Multiple Model/Controller IMC(MMC-IMC) is a model-based control method which uses a set of model/controller pairs rather than a single model/controller to handle all possible operating conditions in the IMC control structure. During operation, one model/controller pair that best fit, for current plant situation is chosen by the switching algorithm. The major drawback of the switching controller is the bad transient performance due to the model error and the use fo linear controller for nonlinear plants. In this paper, we propose a method that transient response of the MMC-IMC using two recurrent neural networks. Simulation result shows that the proposed method represents better performance than the usual MMC-IMC`s.

• 한국항해항만학회지
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• 제40권5호
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• pp.279-284
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• 2016

As the International Maritime English Organization (IMO) model course for Maritime English has been recently revised and updated, the requirements of current changes to both the 2010 STCW Manila Amendments and English education have been actively reviewed. In order to provide practical guidelines for language teaching, a wide range of new pedagogical approaches and their theoretical backgrounds are also suggested. However, considering the current spread of Business English as a Lingua Franca (BELF) and its critical importance in maritime communication, the pedagogical approaches need to be re-evaluated, specifically in terms of teaching pronunciation in order to emphasize clear and effective communication among international interlocutors. Therefore, the core pedagogical elements of pronunciation should be clearly set and provided with consideration for Lingua Franca Core (LFC), which places importance on mutual intelligibility rather than following the rules of native speakers. In this paper, the current trends of BELF in the maritime industry will thus be introduced. Following this, the importance of LFC in maritime communication will be outlined, and its key features will be discussed in terms of effectiveness and clarity of international maritime communications. Finally, a close comparison between LFC and the pronunciation guidelines suggested by the IMO Maritime English model course 3.17 will be conducted, and pedagogical implications for future teaching pronunciation in cross-cultural global maritime industry will be suggested.

• Journal of Information Technology Applications and Management
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• 제19권2호
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• pp.217-231
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• 2012

In the past, companies should make enormous facility investment and acquire a right to do business in order to join communication markets, but now they can do business without important facilities, such as communication networks. Such a movement to ease regulations about companies which want to newly join the communication industry is expected not only to change a competition frame of the mobile communication market but also to greatly affect the entire communication industry. Through this study aiming to look into a way to calculate a reasonable wholesale price related to the government's introduction of the Mobile Virtual Network Operator (MVNO) system, I came up with a following result. I applied the operating profit percentage and the ratio of operating gain to cost to the cost plus model and retail minus model, respectively, to calculate the wholesale price and found that when I calculated with the cost plus model applying the operating profit percentage, I could get the highest wholesale price. On the other hand, I got the lowest wholesale price with the retail minus model by applying the operating profit percentage. Division of expenses and calculation of profit percentage are important factors in calculating the wholesale price and such results are expected to help accurate calculation of the MVNO wholesale price.

• 한국전자통신학회논문지
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• 제18권5호
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• pp.885-894
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• 2023

본 연구는 1인 창업에 대한 경제적 어려움과 리소스(resource) 부족으로 극복할 수 있는 다양한 마케팅 모델을 조사하고 분석하였다. 이전의 연구에서는 통합 마케팅 커뮤니케이션모델에 중점을 두고 진행하였기에 융합적 논의가 부족하였다. 본 연구에서는 포괄적 분석과 시점의 변화를 고려한 역할을 파악하여 IT 콘텐츠 마케팅 커뮤니케이션 모델에 중점을 두고 진행하였다. 그 결과, IT 콘텐츠 커뮤니티 모델을 융합적 가치사슬(Value Chain)방식으로 통합하여 IT 콘텐츠 모델을 개선하고 브랜드 성장과 온라인 프레젠테이션 강화를 도모할 수 있는 새로운 전략적 접근법을 제안할수 있었다. 이를 통해 브랜드 인지도를 효과적으로 높일 수 있는 기반 시설을 마련하게 되었으며, 구체적인 가이드라인을 제공하여 1인 창업의 지속적 성장을 지원하는 방안을 제시할수 있게 되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권2호
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• pp.366-385
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• 2013

In this paper, we propose a compressed sensing (CS) based Wyner-Ziv (WZ) codec using motion-aligned auto regressive model (MAAR) based side information (SI) extrapolation to improve the compression performance of low-delay distributed video coding (DVC). In the CS based WZ codec, the WZ frame is divided into small blocks and CS measurements of each block are acquired at the encoder, and a specific CS reconstruction algorithm is proposed to correct errors in the SI using CS measurements at the decoder. In order to generate high quality SI, a MAAR model is introduced to improve the inaccurate motion field in auto regressive (AR) model, and the Tikhonov regularization on MAAR coefficients and overlapped block based interpolation are performed to reduce block effects and errors from over-fitting. Simulation experiments show that our proposed CS based WZ codec associated with MAAR based SI generation achieves better results compared to other SI extrapolation methods.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.643-646
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• 2005

본 논문에서는 방송망과 통신망이 연동되어 있는 통신 방소 융합 환경하에서 다양한 이동 통신 단말을 가지고 있는 최종 소비자(End-user)에게 멀티미디어 콘텐츠를 서비스 해 주는 서비스 모델을 제시한다. 이 서비스 모델의 특성은 End to End(E2E) media QoS와 소비자 맞춤형 콘텐츠 소비 제공으로써 콘텐츠의 제작에서 적응, 전달, 그리고 최종 소비자에게 맞춤형 콘텐츠 소비를 가능하게 하는 유통 구조를 가지고 있다. 제안된 서비스 모델은 미래의 통방융합 환경에서의 멀티미디어 콘텐츠의 유통을 위한 참조 모델로 사용될 수 있을 것이다.

• 대한임베디드공학회논문지
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• 제5권2호
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• pp.67-76
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• 2010

Although both functional verification and performance evaluation are necessary for the development of effective and reliable communication systems, they have been often performed independently; by functional modeling with formal language tools and by performance modeling with professional network performance evaluation tools, respectively. Separate and repeated modeling of one system, however, would often result in cost increase and inconsistency between the models. This paper proposes an integrated model design approach in order to overcome this problem that evaluates the performance of a communication protocol designed in SDL with SDL-OPNET model conversion. The proposed technique generates OPNET skeleton code from Tau-generated C code of the SDL model by analyzing the relations between SDL and OPNET models. IEEE 802.2 LLC protocol was used as an example of model conversion to show the applicability and effectiveness of the proposed technique.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.133-136
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• 2000

Generally in the case of mobil communication service for long distance sea, unlike heavily populated residential areas, providers need to minimize the service area per base station. Therefore, in this thesis, the 800 ㎒ CDMA system should be extended to give better long distance communication service. This model is used to predict the occurring receiving power of the mobile stations that we simulated and analyzed. As a result, the experiment demonstrated the appropriateness of predicting receiving power using this model.

• ETRI Journal
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• 제42권1호
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• pp.7-16
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• 2020

Assuming omnidirectional antenna reception, the ITU-R recently developed a new propagation model on building entry loss (BEL) for 5G millimeter-wave frequency sharing and compatibility studies, which is a simplified outdoor-to-indoor path loss model. Considering the utilization of high-gain narrow-beamwidth beamforming, the omnidirectional-based ITU-R BEL model may not be appropriate to predict propagation characteristics for directional beamforming scenarios. This paper studies the effects of beamwidth on the ITU-R BEL model. This study is based on field measurements collected with four different beamwidth antennas: omnidirectional, 10° horn, 30° horn, and 60° horn. The measurement campaigns were conducted at two types of building sites: traditional and thermally efficient buildings. These sites, as well as the measurement scenarios, were carefully chosen to comply with the ITU-R BEL measurement guidelines and the ITU-R building types. We observed the importance of accurate beam alignment from the BEL variation range. We were able to quantify the beamwidth dependency by fitting to a model that is inversely proportional to the beamwidth.

• 한국항해항만학회지
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• 제44권2호
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• pp.136-143
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• 2020

Maritime autonomous surface ships (MASS) has been developed over the years. But, there are many unresolved problems. To overcome these problems, this study proposes connected ship navigation system. The system comprises a slave ship and a master ship that leads the slave ship. To implement this system, communication network, route planning algorithms, and controllers are designed. The communication network is built using the transmission control protocol/Internet protocol (TCP/IP) socket communication method to exchange data between ships. The route planning algorithms calculate the course and distance of the slave ship using the middle latitude sailing method. Nomoto model is used as the mathematical model of the slave ship maneuvering motion. Then, the autoregressive with exogenous variables (ARX) model is used to estimate the parameters of Nomoto model. Based on the above model, the automatic steering controller is designed using a proportional-derivative (PD) control. Also, the speed controller is designed for the slave ship to maintain constant distance from the master ship. Sea experiments are conducted to verify the proposed system with two remodeled boats.