• Journal of Positioning, Navigation, and Timing
• /
• v.8 no.3
• /
• pp.119-127
• /
• 2019

COsmicheskaya Sisteyama Poiska Avariynich Sudov Search and Rescue Satellite-Aided Tracking (COSPAS-SARSAT) is an international communication support program to perform search and rescue (SAR) operations in emergency situations by using satellite signals relayed from a beacon. The legacy COSPAS-SARSAT was originally composed of low altitude and geostationary Earth orbit satellites; thus, a limited number of directional dish antennas was sufficient to cover the limited number of visible satellites at the local user terminal. However, the second generation COSPAS-SARSAT newly added the medium Earth orbit satellites, e.g., Global Navigation Satellite Systems (GNSS) to the existing system, so that the number of visible satellites increase dramatically, and the system upgrade to cover all the visible satellites is foreseen. The additional use of planned Korea Positioning System (KPS) to existing GNSS is envisaged to provide a better performance of their SAR service. This paper presents the benefits of the additional use of KPS together with the phased array antennas at the local user terminal of the COSPAS-SARSAT. This is to effectively response to the increase of the number of visible satellites. Numerical simulation is included to evaluate the performance improvement of COSPAS-SARSAT in terms of the number of visible satellites, geometry between satellites and user, and position estimation accuracy.

• Journal of Korean Port Research
• /
• v.10 no.2
• /
• pp.7-15
• /
• 1996

A berth assignment problem has a direct impact on assessment of charges made to ships and goods. A berth can be assigned to incoming vessels and operated in tow different ways: as a common user berth, as a preference berth. A common user berth is a berth that any ship calling at a port may be permitted to use according to her time of arrival and to priorities as determined by the port authority. In this paper, we concerned with various types of mathematical programming models for a berth assignment problem to achive an efficient berth operation. In this paper, we focus on a reasonable berth assignment programming in a public container terminal in consideration of trade-off between server and user. We propose a branch and bound algorithm & heuristic algorithm for solving the problem. We suggest three models of berth assignment to minimizing the objective functions such as total port time, total berthing time and maximum berthing time by using a revised Maximum Position Shift(MPS) with which the trade-off between servers and users can be considered. The berth assignment problem is formulated by min-max and 0-1 integer programming and developed heuristic algorithm to solve the problem more easily instead of branch and bound method. Finally, we gave the numerrical solutions of the illustrative examples.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2022.07a
• /
• pp.19-22
• /
• 2022

In this work, we studied consumers' attractiveness/usefulness perceptions (CAUP) of online commerce product photos when exposed to alternative dark/light user interface (UI) modes. We analyzed time-series EEG data from 31 individuals and performed neuroscience mining (NSM) to ascertain (a) how the CAUP of products differs among UI modes; and (b) which deep learning model provides the most accurate assessment of such neuroscience mining (NSM) business difficulties. The dark UI style increased the CAUP of the products displayed and was predicted with the greatest accuracy using a unique EEG power spectra separated wave brainwave 2D-ConvLSTM model. Then, using relative importance analysis, we used this model to determine the most relevant power spectra. Our findings are considered to contribute to the discovery of objective truths about online customers' reactions to various user interface modes used by various online marketplaces that cannot be uncovered through more traditional research approaches like as surveys.

• Steel and Composite Structures
• /
• v.49 no.1
• /
• pp.1-17
• /
• 2023

Based on Ahmadzadeh-Varvani hardening rule (A-V model), multiaxial ratcheting effect of Z2CND18.12N austenitic stainless steel is simulated by ABAQUS with user subroutine UMAT. The results show that the predicted results of the origin multiaxial A-V model are lower than the experimental data, and it is difficult to control ratcheting strain rate. In order to improve the predicted capability of A-V model, the A-V model is modified. In this study. Moreover, under the assumption of the von Mises yield criterion and normal plasticity flow rule, we develop a numerical algorithm of plastic strain with the improved model to implement the finite element calculation of the model. Internal iteration in the numerical algorithm was implemented with the Euler backward method, which calculated the trial strain for each equilibrium iteration using the consistent tangent matrix. With a user subroutine, the proposed model is programmed into ABAQUS for a user - executable version. By simulating the uniaxial ratcheting of a round bar made of Z2CND18.12N austenitic stainless steel, we observe that the predicted results simulated by ABAQUS with UMAT are compared with the experimental data. The predicted results of the improved multiaxial A-V model are consistent well with the experimental data.

• Journal of Climate Change Research
• /
• v.9 no.1
• /
• pp.1-12
• /
• 2018

There is an emphasis on the importance of adaptation against to climate change and related natural disasters. As a result, various climate information with different time-scale can be used for science-based climate change adaptation policy. From the aspects of Global Framework for Climate Services (GFCS), various time-scaled climate information in Korea is mainly produced by Korea Meteorological Administration (KMA) However, application of weather and climate information in different application sectors has been done individually in the fields of agriculture and water resources mostly based-on weather information. Furthermore, utilization of climate information including seasonal forecast and climate change projections are insufficient. Therefore, establishment of the Cooperation Center for Application of Weather and Climate Information is necessary as an institutional platform for the UIP (User Interface Platform) focusing on multi-model ensemble (MME) based climate service, seamless climate service, and climate service based on multidisciplinary approach. In addition, APCC Integrated Modeling Solution (AIMS) was developed as a technical platform for UIP focusing on user-centered downscaling of various time-scaled climate information, application of downscaled data into impact assessment modeling in various sectors, and finally producing information can be used in decision making procedures. AIMS is expected to be helpful for the increase of adaptation capacity against climate change in developing countries and Korea through the voluntary participation of producer and user groups within in the institutional and technical platform suggested.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.5
• /
• pp.859-871
• /
• 2019

Objectives: The present study aimed to evaluate the usability, quality, and usefulness of the mobile application, CAMBRA-kids, for caries management in preschoolers. Methods: Ninety-one caregivers and preschoolers participated in the user evaluation of CAMBRA-kids. The evaluators assessed the usability, quality, and usefulness of CAMBRA-kids. The collected data were analyzed using R studio 1.2.1335 for Windows (RStudio Inc. 2018, Boston, MA, USA). The evaluations for usability, quality, and usefulness were analyzed with descriptive statistics, Kruskal-Wallis rank sum test, and Wilcoxon rank sum test. Results: On user evaluation, the quality and usefulness of the application scored >3 points, and majority of the users rated the quality and usefulness of the application as high. The quality of the application's system was the highest at 3.68 points, and the actual usage of the application was the lowest at 3.10 points. The application had the highest technological aspect score of 3.20, whereas the content related to oral health information had the lowest score of 3.10/5. Although the application showed no statistically significant differences in the quality and usefulness according to general characteristics, there was a statistically significant difference (p<0.05) between the two when compared between the caries risk group. For all items, the protector of the high-risk group evaluated the quality and usefulness of the application highly. The moderate risk group gave the lowest evaluation score for the application's quality and usefulness. The usability score of the application, according to the user version of the mobile application rating scale (uMARS), was 3.25, and the average engagement score was 2.82 (56.31%). The highest subscale score was 3.63. Conclusions: In this study, we found suitable quality, usability, and usefulness of the mobile application, CAMBRA-kids. In future, the use of this application will contribute to the prevention of dental caries among preschoolers.

• Journal of Digital Convergence
• /
• v.19 no.2
• /
• pp.425-431
• /
• 2021

The purpose of this study is to compare and analyze leading brands of the scooter-sharing system market of Korea, KICKGOING and Lime, in terms of user experience, and to suggest the improvement direction of the applications and scooters of those two services. The assessment was conducted in such a way that the experimental group using scooter-sharing system over a certain frequency would choose the specific service they use most frequently, and complete a questionnaire: based on the reorganized version of the Peter Morville's Honeycomb Model. Based on the results of the experiment, We drew a conclusion that the services need to add navigation features in the application, to provide more simple procedures for reporting breakdown or accident and browsing insurance information, and to improve the user and pedestrian safety levels by gamification, et cetera. We expect this study to help the fast-growing smart mobility market and scooter-sharing systems that represent the market develop into a user-centered way.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.2
• /
• pp.830-842
• /
• 2015

Trust and trustworthiness of web services and organizations is calculated as scalar values. But there is still a certain level of risk for the overall reliability of this value. In this article, we focus on calculating trust values as intervals between upper and lower bounds based on predefined confidence values through an additional confidence probability. This will give us a more realistic approach to the trust assessments between individuals and organizations. We also developed a web-based software tool, TAST (Trust Assessment Software Tool) that collects the web services' evaluation of different customer groups for similar organizations through the user interface and calculates the trust intervals for predefined and previously selected confidence values. Our model uses a weighted calculation of mean and variances of customer groups in specific periods and analyses the total and incremental trust of different customer groups.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.6 no.1
• /
• pp.11-22
• /
• 2000

The paper describes creation methods of background scenes to implement realistic virtual environments in the VRSS (Virtual Reality Ship Simulator). VRSS is next-generation system constructed with virtual tools in a virtual space. Thus, it could have many benefits compared to conventional ship simulators composed with heavy bridge mock-up system and wide visual presentations. In this work, we developed effective 3D object modeling techniques, and constructed virtual harbor scene by using 3D-Webmaster authoring tool. The virtual harbor was built with object-oriented 3D objects modeled to interact with user's action. With the immersion-type VR system, we created virtual harbor environments in a virtual space, and discussed on the naturalness of the scene with test results of SDMPA (Semantic Differential Method for Psychophysical Assessment) by 10 subjects. As the results of subject assessment, all of the participants could felt natural-like harbor. Therefore, we found that the proposed creation methods and procedures of background scene are enabling to fit to the full mission VRSS construction.

• New & Renewable Energy
• /
• v.6 no.2
• /
• pp.5-11
• /
• 2010

This paper reviews three commercial softwares for wind climate data analysis in wind resource assessment; WAsP/Observed Wind Climate, WindRose and Windographer. Windographer is evaluated as the best software because of its variety of input data format, analysis functions, easiness of user interface, etc. For a quantitative understanding of uncertainty depending on software selection, a benchmark is carried out with the met-mast observation dataset at the Gimnyeong Wind Turbine Performance Test Site. It is found that Weibull parameter calculation and air density correction have a dependency on the software so that such uncertainty should be considered when an analysis software is selected. It is confirmed that annual energy production calculated by WAsP using a statistical table of frequency of occurrence may have some error compared to a time-series calculation method used by the other softwares.