• Journal of KIISE
• /
• v.42 no.6
• /
• pp.764-768
• /
• 2015

Requirement of effective image handling methods such as image retrieval has been increasing with the rising production and consumption of multimedia data. In this paper, a method of constructing more effective descriptor is proposed for robust keypoint based image retrieval. The proposed method uses information embedded in the first order and second order derivative images, in addition to the scale space image, for the descriptor construction. The performance of multi-image descriptor is evaluated in terms of the similarities in keypoints with a public domain image database that contains various image transformations. The proposed descriptor shows significant improvement in keypoint matching with minor increase of the length.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.12
• /
• pp.1101-1107
• /
• 2007

this paper, integrity analysis in Korean region using GPS, modernized GPS, Galileo, SBAS and GBAS is given. The simulation results show that Cat. I requirement can be met using modernized GPS and Galileo alone, however, Cat. II and III are not met even augmenting SBAS because of VPL. A more efficient augmentation such as GBAS reduces VPL to meet Cat. II and III requirements in Korean region. This result will be used to design and implement not only an augmentation system but also regional satellite navigation system.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.8
• /
• pp.50-57
• /
• 2003

Controlling rotorcraft to fly precisely through multiple, irregularly, and closely spaced waypoints is a common and practical mission. However, finding an optimal trajectory for this kind of mission is quite challenging. Usability of traditional approaches such as inverse control or direct methods to this kind of problem is limited because of either limitation on the specification of the constraints or requirement of extensive computation time. This paper proposes a method that can easily compute the full trajectory and control history for rotorcraft to pass through waypoints while satisfying other general constraints of states such as velocities and attitudes on each waypoint. The proposed method is applied to rotorcraft guidance problems of slalom and linear trajectory in the middle of general curved trajectory. The algorithm is test for various situations and demonstrates its usability.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.10
• /
• pp.3423-3438
• /
• 2014

In recent years, wearable sensor devices are reshaping the way people live, work, and play. A wearable sensor device is a computer that is subsumed into the personal space of the user, and is always on, and always accessible. Therefore, among the most salient aspects of a wearable sensor device should be a small form factor, long battery lifetime, and real-time characteristics. Thereby, sophisticated applications of a wearable sensor device use real-time operating systems to guarantee real-time deadlines. The deterministic multi-dimensional task scheduling algorithms are implemented on ARC (Actual Remote Control) with relatively limited hardware resources. ARC is a wearable wristwatch-type remote controller; it can also serve as a universal remote control, for various wearable sensor devices. In the proposed algorithms, there is no limit on the maximum number of task priorities, and the memory requirement can be dramatically reduced. Furthermore, regardless of the number of tasks, the complexity of the time and space of the proposed algorithms is O(1). A valuable contribution of this work is to guarantee real-time deadlines for wearable sensor devices.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.5
• /
• pp.107-116
• /
• 2006

This paper deals with a development of night vision imaging system(NVIS) for the KO-1 aircraft. In the modern combat, NVIS has a tendency to be applied for night peculiar mission and pilot mission maximization. KO-1 aircraft, which was the first domestic applied NVIS, is forward air control acquired information of day/night enemy(foe) site and moving of enemy for low altitude flight. We have successfully finished a developmental requirement/criterion, development of system, and construction of test and evaluation through development of NVIS for the KO-1 aircraft. KO-1 aircraft is acquired timely initial operational capability.

• Bulletin of the Korean Space Science Society
• /
• 2008.10a
• /
• pp.28.2-28.2
• /
• 2008

Recently, star sensors have been successfully used as main attitude sensors for attitude control in many satellites. This research presents the star visibility analysis for star trackers and the goal of this analysis is to make sure that the star tracker implementation is suitable to the mission profile and scenario and satisfies the requirement of attitude orbit control system. As a main optical attitude sensor imaging stars, accomodations of a star tracker should be optimized in order to improve the probability of the usage by avoiding the blinding (the unavailability) by the Sun and the Earth. For the analysis, a statistical approach and a time simulation approach are used. The statistical approach is based on the generation of numerous cases, to derive relevant statistics about Earth and Sun proximity probabilites for different lines of sight. The time simulation approach is performed for one orbit to check the statistical result and to refine the statistical result and accomodations of star trackers. In order to perform simulations first of all, an orbit and specific mission profiles of a satellite are set, next the earth proximity probability and the sun proximity probability are calculated by considering the attitude maneuvers and the geometry of the orbit, and then finally the unavailability positions are estimated. As a result, the optimized accomodations of two star trackers are suggested for the low earth orbit satellite.

• Journal of Korean Society of Rural Planning
• /
• v.23 no.2
• /
• pp.29-42
• /
• 2017

Sustainable development is no longer an option, but a requirement. Under this awareness, UN adopted 17 goals for a new sustainable development agenda on September 2015, named 'Sustainable Development Goals(SDGs)'. The Korean Society of Rural Planning(KSRP) is established on July 1994 for the sustainable development of rural areas. On the purpose to quantitatively analyze the research trend of KSRP's publications with the viewpoint of SDGs, the qualitative documents of 17 SDGs and 771 publications were mathematically transformed into vectors and the similarity was numerically measured with the 'Vector Space Model(VSM)'. The results show that 'Sustainable cities and communities(SDG 11)', 'Zero hunger(SDG 2)', 'Life on land(SDG 15)' and 'Responsible consumption and production(SDG 12)' have strong relationships with KSRP, while those of 'Affordable and clean energy(SDG 7)', 'Peace, justice and strong institution(SDG 16)' and 'Gender equality(SDG 5)' are weak. It is also found that the relationships of KSRP publications with 'energy' and 'climate change' issues(SDG 7, 13) were greatly increased during the period of 1995-2016, in spite of their weak relationships.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.12
• /
• pp.1124-1132
• /
• 2011

This paper deals with smooth path generation using B-spline for fixed-wing unmanned aerial vehicles manuevering in 2D environment. Hexagonal cell representation is employed to model the 2D environment, which features increased connectivity among cells over square cell representation. Subsequently, hexagonal cell representation enables smoother path generation based on a discrete sequence of path from the path planner. In addition, we present an on-line path smoothing algorithm incorporating B-spline path templates. The path templates are computed off-line by taking into account all possible path sequences within finite horizon. During on-line implementation, the B-spline curves from the templates are stitched together repeatedly to come up with a reference trajectory for UAVs. This method is an effective way of generating smooth path with reduced on-line computation requirement, hence it can be implemented on a small low-cost autopilot that has limited computational resources.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.11
• /
• pp.968-973
• /
• 2014

Optionally Piloted Vehicle is one of the UAV development technology and method, which can provide the economic and efficient unmanned system. Existing manned aircraft is evaluated through much flight operations and it can supply the reliable aircraft platform, engine and subsystems for operation. In addition, OPV can be operated both manned and unmanned vehicle to satisfy the mission requirement. under the certain flight conditions. This paper describes main development procedures for automatic flight control system of OPV and summarizes the technical issues and results.

• The Korean Journal of Air & Space Law and Policy
• /
• v.18
• /
• pp.105-134
• /
• 2003

This paper describes generic cognitive aspects of the air traffic controller's performance and perceptive activities unveiled through the past literature study. which underlines mental modelling and mental picture presented in the middle of complicated situational awareness and decision making process when air traffic controller comes to determine the distance between aircraft under control to maintain air traffic in a safe, orderly and expeditious way. It also describes human limit in terms of human memory in conjunction with relative workloads and environmental factor. In conclusion, It suggest that ATC authority will take into account the qualitatiive adjustment of training requirement necessary for ATC facility rating and refresher training to allow them more preparedness for better situational awareness and optimal decision making. In this paper controller's behavioral activators affecting their job performance are addressed in perspective of aviation safety.