• Journal of Power Electronics
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• v.16 no.4
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• pp.1407-1414
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• 2016

Unlike existing pulse-width modulation (PWM) techniques, such as sinusoidal PWM and random PWM, the wavelet PWM (WPWM) technique based on a Harr wavelet function can achieve a high fundamental component for the output voltage, low total harmonic distortion, and simple digital implementation. However, the original WPWM method lacks output voltage control. Thus, the practical application of the WPWM technique is limited. This study proposes an improved WPWM technique that can regulate output voltage amplitude with the addition of a parameter. The relationship between the additional parameter and the output voltage amplitude is analyzed in detail. Experimental results verify that the improved WPWM exhibits output voltage control in addition to all the merits of the WPWM technique.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1517-1523
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• 2015

The wavelet PWM (WPWM) technique has been applied in two-level inverters successfully, but directly applying the WPWM technique to three-level inverters is impossible. This paper proposes a WPWM technique suitable for a single-phase three-level inverter. The work analyzes the control strategy with the WPWM and obtains the design of its parameters. Compared with the SPWM technique for a single-phase three-level inverter under the same conditions, the WPWM can obtain high magnitudes of the output fundamental frequency component, low total harmonic distortion, and simpler digital implementation. The feasibility experiment is given to verify of the proposed WPWM technique.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.10-16
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• 2003

Under the concept of global economy, the enterprises are assigning design and production environments around the world in different areas. In shipbuilding companies, a serious problem of information exchange emerges as companies use traditional hardware and very distinct softwares appropriate to their field of expertise. To overcome the decreased productivity due to the interruption of information, the concept of simultaneous engineering and concurrent design becomes very significant. In this article, the concept oj collaborative design based on internet environments is described. Especially, the core technologies to achieve collaborative design environments among shipbuilding companies, ship owners, ship classification societies, model basin, and consulting companies are adopted.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.62-72
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• 2001

In the countries of USA, UK, etc, which have the advanced submarine design technologies, the digital mockup actively applies in the naval ship and the submarine design, because it has many advantages such as the reduction of shipbuilding periods and costs, the potential of easier design changes, the combination of visualization with realistic behavior and so on. This paper includes the architecture development methods of digital mockup system and presents the S/W and H/W architecture scheme and the methods of 3D CAD modelling system of a submarine hull and machineries for the conceptual design verification.

• The Korean Journal of Archival Studies
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• no.42
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• pp.245-285
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• 2014

This study aims to implement a model for developing participatory labor archives for shipbuilding labor archives in young-do, Busan, and to find possibilities of building digital labor archives as participatory ones. The methodology of locality documentation has been applied, and locality archives accepting participation of people with experiences from shipbuilding industry have been examined. Omeka was applied because it is an open-source software and provides additional functions which support various user participations and web-publishing. Following the the model, firstly, a preliminary investigation was conducted and research of participatory agents and records was proceeded. Secondly, it collected and described information of the agents and records by institutions with records and provenance. Thirdly, it developed archival contents specific to events, persons and workplaces in association with archival information. For the follow-up study, plugins were installed and tested to apply for further experiment with participation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.867-874
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• 2021

The IoT (Internet of Things) technology is rapidly becoming an important consideration in many engineering fields in the current 4th industrial era. In recent years, the concepts of digital shipbuilding and smart factories have been adopted as trends in shipyards. However, there is active interest in research on implementing autonomous driving in autonomous vehicles and airplanes, which is currently available in commercial form in a limited capacity. The present study is regarding the path-tracking performance of a boat to accomplish an autonomous driving mission using a flight controller (FC) and real-time kinematic (RTK) global positioning system (GPS) based on an open-source Ardupilot; an actual sea test is also performed using this system on a calm lake. The boat's mission is to evaluate the maneuverability of the self-driving process to a specific point and returning to the home position. For a given speed, the difference between the preset mission trajectory and actual operational trajectory was analyzed, and a series of studies were conducted on the applicability of the system to ships. In addition, the movements and maneuverability of the OmniX-type hull with four propellers were investigated, and the driving path-tracking performance was observed to increase by a maximum of 48%.

• Information Systems Review
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• v.6 no.2
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• pp.227-242
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• 2004

With the advent of the digital economy, the business eco-system has been changing from the competition system across individual companies to that of supply chains. Under the rapidly changing business environment, it becomes true that the competitive power of the steel maker depends on the shipbuilding company, an important customer of the steel maker. Accordingly, e-partnering between a steel maker and shipbuilding companies becomes important. Schemes of developing e-partnering are presented as follows: implementation of the inter-communication system, day/sequence order and supply, improvement of infrastructure such as transport, quay etc.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.400-405
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• 2022

Legislative approaches to regulating the digital sex industry are increasingly being debated at the international and national levels. There is a trend showing an increased interest in the decriminalization of sex work. At the same time, in many countries, activities related to digital prostitution remain criminalized. In this regard, it is important to analyze the international legal experience of the criminalization and decriminalization of digital prostitution, as well as to pay attention to the key problematic issues that arise during the criminalization and decriminalization of such an issue. The object of the study is the international experience of criminalization and decriminalization of digital prostitution. The subject of the study is social relations that arise, change, and cease during the criminalization and decriminalization of digital prostitution. The research methodology consists of such methods as philosophical, logical, special-legal, system analysis methods, and formal-dogmatic methods. Research results. As a result of the study of the international legal experience of criminalization and decriminalization of digital prostitution, it was concluded that the criminalization and/or decriminalization of digital prostitution is treated differently in different countries. Workers in this industry advocate decriminalization, not legalization, because decriminalization puts power directly in the hands of sex workers and creates no legal barriers. Countries that have decriminalized digital prostitution believe that sex work is real work and should be treated respectfully, and banning resources such as OnlyFans is not in favor of such workers. Regarding positions on the criminalization of prostitution, countries use different models of such criminalization, including the model of legalization of digital prostitution, which, on the one hand, allows prostitution, but establishes criminal liability for deviations from the rules established by the state.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.641-649
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• 2009

There were many simulation models that made for validation of industrial environment and estimate of efficiency to be constructed. And there will be more simulation models made for same reason, too. Already, there have been a lot of simulation models in industry field and scholar labs. To reuse these simulation models, it is necessary to find common properties and make the high abstract simulation model. Based on this idea, this study shows to define the high abstract simulation model to be able to specialize in need and to make the software framework for connecting the specific simulation model to the abstract model. And it is held up as the example that applying the simulation framework to the Ship Panel Block shop simulation model.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.243-253
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• 2013

As global competition is more intensive, SCM is becoming more and more important in order to achieve competitiveness. It is necessary for firms to understand weak points among the integrated supply chain through supply chain assessment in order to implement SCM successfully and cost-effectively. In this paper, we review previous studies of SCM performance measurements and propose a supply chain assessment framework for shipbuilding industry, which is one of the major ETO industry. Based on 3 supply chain domains which are demand, supply, and product management, we decompose the whole supply chain process into 3 level lower processes and propose capability measurement matric for shipbuilding firms. A case study has been conducted to validate the proposed framework and results are presented at the end.