• Journal of the Society of Naval Architects of Korea
• /
• v.59 no.1
• /
• pp.1-8
• /
• 2022

To understand physical phenomena of ship maneuvering deeply, a numerical study based on computational fluid dynamics is required. A computational method that can simulate the interaction between the ship hull, propeller, and rudder will provide informative local flows during ship maneuvering tests. The analysis of local flows can be applied to improve a physical model of ship maneuvering that has been widely used in maneuvering simulations. In this study, the numerical program named as WAVIS that has been developed for ship resistance and propulsion problems is extended to simulate ship maneuvering by free-running tests. The six degree-of-freedom of ship motion is implemented based on Euler angles and the overset technique is applied to treat the moving grid of ship hull and rudder. The propulsion force due to a propeller is calculated by a panel method that is based on the lifting-surface theory. The newly extended code is applied to simulate turning and zig-zag tests of KCS and the comparison with the available experimental data has been made.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.11
• /
• pp.1663-1669
• /
• 2021

This paper considers the cooperative control problem for multiple leaders and a single follower with interactions. The leaders are controllable, and the follower has interactions with all leaders and is controlled by the interactions. Then, we study the cooperative control problem that achieves the consensus by controlling the leaders. The leaders and the follower are modeled by the single-integrator and the double-integrator, respectively, and it is assumed that the interactions have the nonlinearities. The leaders can estimate the interaction between the follower and exchange the estimated information with neighbors. Then, this paper proposes the consensus-based cooperative control algorithm using the information exchange of the estimated interactions and the virtual velocity variables to achieve the velocity consensus. We analyze the convergence of the agents to the common state based on the Lasalle's Invaraince Principle. Finally, we provide the numerical example to validate the theoretical results.

• Smart Media Journal
• /
• v.11 no.8
• /
• pp.55-64
• /
• 2022

In the recent education market, Edutech technology, in which various digital technologies are grafted into the education, is being actively applied due to the 4th industrial revolution and the development of ICT. In particular, realistic experiential learning contents that can provide realistic and immersive learning in a virtual space are in the spotlight and are being expanded to each field. However, in the field of Korean medicine education, the introduction of ICT is delayed due to the nature of Korean medicine, difficulties in apprenticeship education, quantitative education, and the absence of an objective evaluation system. Therefore, in this study, we propose a digital technology application for acupuncture and acupuncture points, where practice is particularly important in Korean medicine. Various methods of acupuncture and acupoints education using AR, MR, IoT and Touch-Display Table will provide an opportunity to change the paradigm of Korean medicine education and further contribute to the globalization of Korean medicine.

• Journal of Internet of Things and Convergence
• /
• v.8 no.3
• /
• pp.63-68
• /
• 2022

Due to COVID-19, many paradigm shifts in existing manufacturing facilities and the expansion of non-face-to-face services are accelerating worldwide. A representative technology is digital twin technology. Such digital twin technology, which existed only conceptually in the past, has recently become feasible with the construction of a 5G-based network. Accordingly, this paper designed and implemented a part of the USB process to enable digital twins based on OPC UA communication, which is a standard interlocking structure, between real object objects and virtual reality-based USB process in accordance with this paradigm change. By reflecting the physical characteristics of real objects together, it is possible to simulate real-time synchronization of these with real objects. In the future, this can be applied to various industrial fields, and it is expected that it will be possible to reduce costs for decision-making and prevent dangerous accidents.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.2
• /
• pp.626-643
• /
• 2023

As mobile forensics has emerged as an essential technique, the demand for technology development, education and training is increasing, wherein images are used. Academic societies in South Korea and national institutions in the US and the UK are leading the Mobile Forensic Image development. However, compared with disks, images developed in a mobile environment are few cases and have less active research, causing a waste of time, money, and manpower. Mobile Forensic Images are also difficult to trust owing to insufficient verification processes. Additionally, in South Korea, there are legal issues involving the Telecommunications Business Act and the Act on the Protection and Use of Location Information. Therefore, in this study, we requested a review of a standard model for the development of Mobile Forensic Image from experts and designed an 11-step development model. The steps of the model are as follows: a. setting of design directions, b. scenario design, c. selection of analysis techniques, d. review of legal issues, e. creation of virtual information, f. configuring system settings, g. performing imaging as per scenarios, h. Developing a checklist, i. internal verification, j. external verification, and k. confirmation of validity. Finally, we identified the differences between the mobile and disk environments and discussed the institutional efforts of South Korea. This study will also provide a guideline for the development of professional quality verification and proficiency tests as well as technology and talent-nurturing tools. We propose a method that can be used as a guide to secure pan-national trust in forensic examiners and tools. We expect this study to strengthen the mobile forensics capabilities of forensic examiners and researchers. This research will be used for the verification and evaluation of individuals and institutions, contributing to national security, eventually.

• Journal of the Korea Society for Simulation
• /
• v.18 no.2
• /
• pp.77-89
• /
• 2009

Visual tracking technique is one of the essential things which are very important in the major fields of modern society. While contour tracking is especially necessary technique in the aspect of its fast performance with target's external contour information, it sometimes fails to track target motion because it is affected by the surrounding edges around target and weak egdes on the target boundary. To overcome these weak points, in this research it is suggested that PDMs can be obtained by generating the virtual 6-DOF motions of the mobile robot with a CCD camera and the image tracking system which is robust to the local minima around the target can be configured by constructing Active Shape Model in modular base. To show the effectiveness of the proposed method, the experiment is performed on the image stream obtained by a real mobile robot and the better performance is confirmed by comparing the experimental results with the ones of other major tracking techniques.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.23 no.1
• /
• pp.10-19
• /
• 1986

This is the last part of the four-part describing the development of a packet-switched computer communication network named the KORNET. In this paper we describe the design and implementation of the packet assembler/dissassembler (PAD) protocol for the asynchronous channel service, and of the network management softwares. The line processing module-B(LPMB) system supporting the asynchronous line includes a PAD protocol, a packet mode DTE/DCE protocol converting to the X.25 protocol, and the asynchronous receiver/transmitter(ART) software. The network management software is operated in master central processing module(MCPM) which includes virtual circuit management (VCM) managing the user channel, the routing management and the high level protocol for communication between the network management center (NMC) and the network node processor(NNP). In this paper, the design, implementation and operation of the softwares for the above service functions will be described in detail.

• International Journal of Knowledge Content Development & Technology
• /
• v.13 no.1
• /
• pp.27-41
• /
• 2023

The outbreak of the corona virus diseases (COVID-19) in the late 2019 has affected all facets of educational system including library and information services. Reference services, an important aspect of library services are not exempted from this impact. This study therefore, investigated the impact of COVI\D-19 pandemic on the use of reference services and sources by postgraduate students using Kenneth Dike Library (KDL), University of Ibadan, as a case study. Using descriptive survey of correlational type, the study adopted the use of structured questionnaire to randomly select three hundred (300) postgraduate users of reference sources and services in KDL using online survey monkey. Of the three hundred (300) copies, two hundred and twenty three (223) copies, repre- senting 74.3% were retrieved and used for analysis. Findings revealed that, in spite of COVID-19 pandemic, most postgraduate students used Current Awareness Services (203, 91.0%, mean = 3.19), Reference Sources (202, 90.5%, mean = 3.18) and On-line Public Access Catalogue (195, 87.4%, mean = 3.13); low frequency of bibliotherapy (mean=2.22), Reader's Advisory services (mean=2.30) and inter-library loan (mean=2.13) and that COVID-19 pandemic had high impact on post- graduate students' use of reference services in Kenneth Dike Library, University of Ibadan. Based on the findings, recommendations were made that library management should consider the adoption of virtual reference services (VRS) in addition to the conventional mode of refer- ence services to enhance patronage in the COVID-19 era. The library users should also be trained on how to take advantage of the COVID-19 pandemic to learn new skills in the digital space that will eventually optimize the usage of the library remotely.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.26 no.1
• /
• pp.102-112
• /
• 2023

This research mainly focuses on the transport and dispersion of chemical agent plume according to the Lagrangian Puff Model and Lagrangian Particle Model of NBC_RAMS(Nuclear, Biological, Chemical Reporting And Modeling S/W System). NBC_RAMS was developed with the purposes of estimating the fate of Chemical, Biological, and Radioactive(CBR) agent plumes and evaluating damages in the Republic of Korea. First, it calculates the local weather pattern, i.e. wind speed, wind direction, and temperature, by considering the effects of land uses and topography. The plume behaviors are calculated by adopting the Lagrangian Puff Model(LPFM) or Lagrangian Particle Model(LPTM). In this research, we assumed a virtual chemical agent exposure event in a stable atmospheric condition during the summer season. The plume behaviors were estimated by both LPFM and LPTM on the used area(urbanized and dry area) and the agricultural land. The higher heat flux in the used area led to stronger winds and further downward movement moving of the chemical agent than the farmland. The lateral dispersion of the chemical plume was emphasized in the Lagrangian Puff Model because it adopted Gaussian distribution.

• Journal of IKEEE
• /
• v.26 no.1
• /
• pp.89-94
• /
• 2022

The W-band (75-110GHz) is a band that can utilize at least 10 times more bandwidth than the existing 5G band. Therefore, it is one of the bands suitable for future mobile communication that requires high speed and low latency, such as virtual and augmented reality. However, since the wavelength is short, it has a high path loss and is very sensitive to the atmospheric environment. Therefore, in order to develop a W-band communication system in the future, it is necessary to analyze the characteristics of path loss according to the channel environment. In this paper, to analyze the characteristics of the W-band path loss, the random forest technique was used, and the influence of the channel parameters according to the distance section was analyzed through the path loss data according to various channel environment parameters. As a result of the simulation, the distance has the highest influence on the path loss in the short distance, and the other channel environment factor is almost ignored. However, as the distance section became longer, the influence of distance decreased while the impact of clutter and rainfall increased.