• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.11
• /
• pp.979-987
• /
• 2012

This paper implements and integrates algorithms for terrain following of UCAVs (Unmanned Combat Aerial Vehicles): trajectory generation, guidance, and navigation. Terrain following is very important for UCAVs because they perform very dangerous missions such as Suppression of Enemy Air Defences while the terrain following can improve the survivability of UCAVs against from the air defence systems of the enemy. To deal with the GPS jamming, terrain referenced navigation based on nonlinear filter is chosen. For the trajectory generation, Voronoi diagram is adopted to generate horizontal plane path to avoid the air defense system. Cubic spline method is used to generate vertical plane path to prevent collisions with ground while flying sufficiently close to surface. Follow-the-Carrot and pure pursuit tracking methods, which are look-ahead point based guidance algorithms, are applied for the guidance. Numerical simulation is performed to verify the performance of the integrated terrain following algorithm.

• Journal of the Korea Convergence Society
• /
• v.9 no.7
• /
• pp.269-276
• /
• 2018

As the particulate matter (PM) is fatal for human being, the government authorities try to lessen PM with a variety of policy instruments. To increase the efficiency of the policy, we need to understand people's perception and risk avoidance on PM. Thus, the research explored what attribution styles, involvement, and perceived health status have an influence on preventive intention. First, we found three attribution styles on PM occurrence through factor analysis: daily life(DL), domestic industry & environment(DI&E), and Chinese industry & environment(CI&E). We also found that involvement(${\beta}=.465$, p<.001), CI&E(${\beta}=.222$, p<.001), DL(${\beta}=.173$, p<.01), and DI&E(${\beta}=.143$, p<.05) have an influence on preventive intention in order. Finally we discussed suggestions for future study.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.6 no.1
• /
• pp.17-27
• /
• 2012

This study provides development information on Omni-Wheel Drive Rider Robot, futuristic electric scooters, with autonomous driving systems that are used for people including the disabled and senior. Also, it is meaningful in suggesting alternatives to replace motorized wheelchairs or electric scooters for the future. Prior to development of Omni-Wheel Drive Rider Robot with autonomous driving systems, it surveyed 49 people, including 18 people who own electric scooters and 31 senior people who have not. The summary of the survey is as follows. First, inconveniences during riding and exiting and short mileage due and safety driving to problems of recharging batteries are the most urgent task. For these problems, the study shows that charging time of batteries, mileage, armrests, footrests, angle of a seat are the primary considerations. Second, drivers prefer joystick over steering wheels because of convenience in one-handed driving against dangers from footrest and carriageways sloping roads, paving blocks. One-handed driving can reduce driving fatigues with automatic stop systems. Moreover, the study suggests many design factors related to navigation systems, obstacle avoidance systems, omni-wheels, automatic cover-opening systems in rainy.

• Science of Emotion and Sensibility
• /
• v.13 no.4
• /
• pp.711-720
• /
• 2010

This study is aimed to compare choices on interaction problems, and to consider the reason of the choices. It was expected that the interaction problems are influenced from national culture, age, gender and so on. The first interaction problem in this study is default answer button when user operates to delete all messages on SMS in-box. Second one is action when pop-p window warning dangerousness of install showed on web browsing. The third one is type(analog/digital) and information expression of control panel on soup maker. 639 Korean data and 784 data from China, Japan and the Netherlands are analyzed through cross-tabulation and chi-square test. In the results, many Japanese choose 'No' answer at SMS delete problem, while many Dutch choose 'Yes'. The result suggests that uncertainty avoidance effect on interaction problems. On warning pop-up, Younger generation and men choose actively 'install' than older one and women. On type of control panel, Dutch subjects preferred analog type than other countries' subjects. On expression of control panel, older generation and individualistic subjects relatively preferred text style than other style.

• Journal of Advanced Navigation Technology
• /
• v.19 no.4
• /
• pp.288-298
• /
• 2015

For the commercialization of unmanned aircraft, we must validate the safety of the air/ground collision alert systems (CAS). The validation procedure of CAS requires the flight test which is not only expensive but also dangerous. To alleviate this problem, we need the simulation based validation process for the CAS. We developed an integrated UAV simulation (IUS) environment which interconnect the flight simulator, the Matlab/Simulink, and a target avionics simulation model. We developed the collision warning module of the TCAS and tested using IUS and flight encounter models. Using IUS, we can evaluate the performance and reliability of a target avionic system at the preliminary design stage of a development life cycle.

• The Journal of Society for e-Business Studies
• /
• v.22 no.4
• /
• pp.117-128
• /
• 2017

The increased national utilization of Bitcoin results in multiple complications. Therefore, there are continuous debates on the subject, the main point being how to characterize Bitcoin's asset nature. The following study bases, focusing on the function value, justifies Bitcoin's asset characterization. Using regression analysis to construct relations between gold and indexes such as CPI, DXY, and S&P500 as well as the relation between Bitcoin and the previously mentioned indexes, the question of whether gold and Bitcoin reacted in a similar fashion to the same indicators was examined. The results conclude that Bitcoin has similarities with gold, showing that it is risk averse and an investable commodity in lieu to profitability when it comes to inflation and currency value. When considered with price volatility, the main force behind the function of investment asset, categorizing Bitcoin as a high-risk financial investment asset rather than as a currency within the system would be more effective for management.

• Environmental and Resource Economics Review
• /
• v.21 no.1
• /
• pp.129-156
• /
• 2012

This study analyzes the contribution to the national economy of the stable water supply through managing multi-purpose dam. For the analysis, we consider 17 major multi-purpose dams and build a CGE model with summer water and winter water being the production factors as the base year of 2007. We analyze the economic impact of meeting water demand due to the dam management and estimate the risk premium of reducing the uncertainty of water supply. The analysis results show a significant production decrease in the industries of agriculture, forestry and fisheries and tap water as well as the food and beverage industry using the former industries' output as intermediates in the production and show an production increase largely in steel industry and electronic and electrical industries. Being compared to the benchmark solution, GNP is analyzed as being reduced by 0.22~0.68%. Meanwhile, the risk premium is estimated to be about 4 billion to 24 billion won for the value 01 the measure of relative risk aversion in the range 01 0.5 to 3.0.

• Journal of Korean Society of Transportation
• /
• v.27 no.4
• /
• pp.137-143
• /
• 2009

It is necessary to develop driving assistant information in order to prevent a rear-end collision with a crashed car which is at the blind curve on highway. Laboratory experiments were performed using a driving simulator to keep the traffic environment constant. This research was evaluated the effect of driver behavior according to providing collision avoidance information which was consisted of advisory, caution, and warning information by the dangerous degree of traffic situation. Driver behavior was evaluated to analyze the collision avoidance with a crashed car, and glance behavior was examined to measure the eye movements to the display on which provided the collision avoidance information. After experiment, the significance was evaluated on provided collision avoidance information. As the result of this research, the number of collision accident is reduced when the phased information was provided. In addition, it is clear that auditory information is more important than visual information in the case of providing the second information.

• Journal of Korean Society of Transportation
• /
• v.32 no.5
• /
• pp.441-451
• /
• 2014

This study proposes a novel performance measure, which is referred to as Hazardous Spacing Index (HSI), to be used for evaluating safety of traffic stream on freeways. The basic principle of the proposed methodology is to investigate whether drivers would have sufficient stopping sight distance (SSD) under limited visibility conditions to eliminate rear-end crash potentials at every time step. Both Road Weather Information Systems (RWIS) and Vehicle Detection Systems (VDS) data were used to derive visibility distance (VD) and SSD, respectively. Moreover, the K-Nearest Neighbors (KNN) method was adopted to predict both VD and SSD in estimating predictive HSIs, which would be used to trigger advanced warning information to encourage safer driving. The outcome of this study is also expected to be used for monitoring freeway traffic stream in terms of safety.

• Journal of Technology Innovation
• /
• v.20 no.3
• /
• pp.1-28
• /
• 2012

This study conducted a qualitative analysis on the Korea's nuclear energy sector in 2030 through scenario-based strategic foresight method. Specifically, the relationships between environmental influencing factors of the future nuclear energy sector was examined from a multi-dimensional perspective on the basis of STEEP analysis and network analysis. In addition, scenario planning method was used with key uncertainty factors (KUF) to create three predictable strategic scenarios including optimistic, business as usual, and pessimistic. Common strategies that need to be urgently pursued as well as the maximum risk avoidance strategies for each scenario were also presented. This study further identified energy pricing, global economic trend, competitiveness in nuclear technology, and marketing capability as key uncertainty factors in the future nuclear energy industry sector. In order to furnish effective export strategy in the future nuclear energy sector, it was also suggested that government policy should adopt following measures as top priorities: securing nuclear safety technology, educating nuclear engineers, securing nuclear resources such as uranium, increasing nuclear capability and so on. The implications and limitations of this study were then discussed based on research findings.