• Journal of Satellite, Information and Communications
• /
• v.11 no.4
• /
• pp.33-38
• /
• 2016

As a communications system and using the wireless devices is increased at the world, the interference among devices at 2.4GHz band become issue. New complex content technology as education, concert, broadcast, thema-park are developed between Virtual Reality technology and tradition. That is expect an annual growth rate of more than 14%. Almost Virtual Reality devices use motion sense or a wireless joystick. Therefore it is necessarily to analyze the coexistence between Virtual Reality devices and Wi-Fi in the ISM band. The interference scenario and propagation of the Extended Hata Model was established to analyze the interference from WLAN into Virtual Reality devices. Through simulation results based on Monte-Carlo principle, separation frequency was obtained to protect WLAN interference from Virtual Reality devices.

• Journal of Navigation and Port Research
• /
• v.40 no.4
• /
• pp.189-196
• /
• 2016

We propose a virtual sailor training platform which supports emergency drills for ship's fire in virtual environment. Proposed platform not only enhances training efficiency by providing immersiveness, but also enables a consolidated virtual training due to the network-based multiplayer capabilities. Based on the offline fire simulation results using FDS and CFAST the platform visualizes a realistic fire spread in real-time. The training platform on the basis of the fire training material of the maritime safety education institute induces equipment proficiency and environment adaptation throughout immersive virtual environment in addition to procedure proficiency as well. In the implementation we showed that the equipment and environment controls and telepresence improve the training proficiency and enable collaborative virtual training that participates multiple trainees and induces cooperation for a common goal. Implementation of the platform demonstrated the skill mastery capability of the drill such as efficient fire apparatus controls and passenger controls.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.6A
• /
• pp.583-588
• /
• 2004

For the Explicit Multicast (Xcast) scheme, we propose a scheme that provides dynamic group membership and supports a large, dense multicast group. To do so, we use a hierarchical joining mechanism, where a domain agent joins a group on behalf of hosts. In our scheme, a sender transmits multicast packets to a domain agent, and then the agent forwards the packets to receivers in a domain. A host can join or leave a group at my time via the domain agent. Thus, a destination field of the Xcast header has addresses of domain agents instead of hosts. Simulation results show that our scheme can reduce more the Xcast header size and cost in forwarding packets than the Xcast, especially for a large multicast group. Like traditional multicast schemes, our scheme can support large multicast group members.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.652-658
• /
• 2016

In this paper, the theoretical research and simulation using the Finite Element Method (FEM) to design and form a micro-pattern for an ultrasonic horn is described. The present method is based on an initial design estimate obtained by FEM analysis. The natural and resonant frequencies required for the ultrasonic tool horn used for forming the fine pattern were predicted by finite element analysis. FEM analysis using ANSYS S/W was used to predict the resonant frequency for the optimum technical design of the ultrasonic horn vibration mode shape. When electrical power is supplied to the ultrasonic transducer, it is converted into mechanical movement energy, leading to vibration. The RFID TAG becomes the pattern formed on the insulating sheet by using the longitudinal vibration energy of the ultrasonic tool horn. The FEM analysis result is then incorporated into the optimal design and manufacturing of the ultrasonic tool horn.

• Korean Journal of Agricultural Science
• /
• v.46 no.4
• /
• pp.723-735
• /
• 2019

The power-train is the most important component of an agricultural tractor. In this study, the strength of the driving gear transmission of an 82 kW-class tractor was analyzed using equivalent torque during plow tillage. The load measurement system consisted of an engine revolution speed sensor, torque-meters, revolution speed sensors for four axles, and pressure sensors for two hydraulic pumps. The load data were measured during plow tillage for four speed stages: F2 (2.78 km/h), F5 (5.35 km/h), F7 (7.98 km/h), and F8 (9.75 km/h). Aspects of the gear-strength such as bending stress, contact stress, and safety factors were analyzed under two torque conditions: the equivalent torque at the highest plow load for the F8 speed stage and the maximum engine torque. The simulation results using KISSsoft showed that the maximum engine torque conditions had a lower safety factor than did the highest equivalent torque condition. The bending safety factors were > 1 at all gear stages, indicating that gear breakage did not occur under actual measured operating conditions, nor under the maximum torque conditions. However, the equivalent torque condition in the contact stress safety factor was > 1, and the maximum torque condition was < 1 at the first gear pair. The method of analysis using the equivalent torque showed lower stress and higher safety factor than did the method using maximum torque. Therefore, when designing a tractor by applying actual working torque, equivalent torque method would support more reliable product development.

• Archives of Craniofacial Surgery
• /
• v.21 no.4
• /
• pp.225-228
• /
• 2020

Background: The aim of this study is to develop a two-stage training module using radish and swine scapular cartilage for carving ear cartilage. Methods: In the first stage, white radish was cut in 3-6 mm thick slices. The ear cartilage framework was carved using a graver and the helix and antihelix were fixed with pins. In the second stage, swine scapular cartilage was obtained. The thickness varied 3-6 mm. The ear cartilage framework was made. And triangular fossa and scaphoid fossa were carved with graver. A curvilinear cartilage for helix was assembled to the framework by pin fixing. Six participants were recruited for an ear reconstruction training workshop and figures of the cartilage framework were provided. Participants were asked answer the pre-workshop questionnaire and post-workshop questionnaire on a Likert scale to rate their satisfaction with the outcome. Results: On the pre-workshop questionnaire, participants indicated that they did not have sufficient knowledge and skill for fabricating the ear cartilage framework (1.5±0.5 using white radish; 1.3±0.5 using swine scapular cartilage). On the post-workshop questionnaire, participants responded that they had learned useful knowledge from this workshop, reflecting a significant improvement (3.8±1.0 using white radish; 4.0±1.1 using swine scapular cartilage). They also indicated that they had become somewhat confident in this skill (4.2±0.8 using white radish; 4.3±0.5 using swine scapular cartilage. The participants generally found the workshop satisfactory (practically helpful, 4.7±0.5; knowledge improved, 4.8±0.4; satisfied with course, 4.5±0.5; would recommend to others, 4.8±0.4). Conclusion: This model can be useful for ear reconstruction training for medical personnel.

• Journal of Korea Game Society
• /
• v.9 no.1
• /
• pp.93-103
• /
• 2009

A Serious Game helps the learners to recognize the problems effectively, grasp and classify important information needed to solve the problems and convey the contents of what they have learned. Owing not only to this game-like fun but also to the educational effect, The Serious Game can be usefully applied to education and training in the areas of scientific technology and industrial technology. This study proposes the Serious Game that users can apply to biotechnology by using intuitive multi-modal interfaces. In this study, a stereoscopic monitor is used to make three dimensional molecular structures, and multi-modal interface is used to efficiently control. Based on a such system, this study easily solved the docking simulation function, which is one of the important experiments, by applying these game factors. For this, we suggested the level-up concept as a game factor that depends on numbers of objects and users. The proposed system was evaluated in performance comparison in result time of a new drug design process on AIDS virus with previous approach.

• Journal of Korean Academy of Nursing
• /
• v.40 no.2
• /
• pp.151-160
• /
• 2010

Purpose: The purpose of this study was to evaluate the effects of teaching method using Standardized Patients (SPs) on nursing competence, self-directed learning readiness, and problem solving ability-focusing on subcutaneous insulin injection. Methods: This research was a nonequivalent control group non-synchronized post-test design. The subjects consisted of 62 junior nursing students at E University. Scenarios to train SPs and checklists to evaluate the students' competence were developed by our research team. The experimental group (n=31) participated in the teaching class using SPs. The control group (n=31) received traditional practice education. The collected data were analyzed with descriptive analysis, $\chi^2$/Fisher's exact test, t-test, Pearson's correlation coefficient, and Cronbach's $\alpha$ using SPSS WIN 14.0 Program. Results: The mean scores of competence, self-directed learning readiness, and problem solving were significantly higher in the experimental group than the control group. Conclusion: As confirmed by this research findings, the teaching method using SPs was more effective than the traditional method to improve junior nursing students' competence, self-directed learning readiness, and problem solving. Therefore, It is necessary to develop a various of scenarios and to testify their effectiveness.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.120-122
• /
• 2015

In this paper, we proposed an algorithm of the unnecessary copied message inhibition using dynamic density what is called DDIM(Dynamic Density-based Inhibited Message diffusion) in DTNs(Delay Tolerant Networks). Existing DTN routing algorithms as Epidemic and Spray and Wait have some problems that occur large overhead in dense network due to the thoughtless message diffusion. Our proposed method, the DDIM, determines adjusted number of copied message through dynamic node density that is calculated using node's radio coverage and neighbor nodes in period time to solve message diffusion problem. It decrease overhead without losing message delivery ratio and increased latency through reducing message diffusion. In this paper, we compare delivery ratio, average latency and overhead of proposed algorithm, DDIM, and existing DTN routing algorithm and prove enhanced performance through simulation results.

• Structural Engineering and Mechanics
• /
• v.57 no.3
• /
• pp.569-585
• /
• 2016

This paper highlights a case study that investigates the behaviour of existing bridge, West Terrace Bridge, induced by horizontal seismic loading. Unfortunately the lack of past information related to seismic activity within the NSW region has made it difficult to understand better the capacity of the structure if Earthquake occurs. The research was conducted through the University of Western Sydney in conjunction with Railcorp Australia, as part of disaster reduction preparedness program. The focus of seismic analyses was on the assessment of stress behaviour, induced by cyclic horizontal/vertical displacements, within the concrete slab and steel truss of the bridge under various Earthquake Year Return Intervals (YRI) of 1-100, 1-200, 1-250, 1-500, 1-800, 1-1000, 1-1500, 1-2000 and 1-2500. Furthermore the stresses and displacements were rigorously analysed through a parametric study conducted using different boundary conditions. The numerical analysis of the concrete slab and steel truss were performed through the finite element software, ABAQUS. The field measurements and observation had been used to validate the results drawn from the finite element simulation. It was illustrated that under a YRI of 1/1000 the bottom chord of the steel truss failed as the stress induced surpassed the ultimate stress capacity and the horizontal displacement exceeded the allowable displacement measured in the field observations whereas the vertical displacement remained within the previously observed limitations. Furthermore the parametric studies in this paper demonstrate that a change in boundary conditions alleviated the stress distribution throughout the structure allowing it to withstand a greater load induced by the earthquake YRI but ultimately failed when the maximum earthquake loading was applied. Therefore it was recommended to provide a gap of 50mm on the end of the concrete slab to allow the structure to displace without increasing the stress in the structure. Finally, this study has proposed a design chart to showcase the failure mode of the bridge when subjected to seismic loading.