• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.2
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• pp.1-6
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• 2012

Four dimensional(4-D) trajectory modeling is conducted based on flight plan. The flight plan is divided into several segments which represent certain operating flight modes. Thrust, drag and fuel consumption rate of an aircraft are calculated using BADA provided by Eurocontrol. The trajectory is modeled with the rate of climb/descent calculated with Total-Energy Equation. The simulation results with a typical aircraft and its flight plan indicate that the trajectory modeled corresponds well with the suggested flight plan. The performance profiles including total endurance time and time history for speed, thrust, drag and fuel consumption were also appropriately generated.

• STI Policy Review
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• v.7 no.2
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• pp.16-34
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• 2016

This study aims to identify the chronological trajectory of university science parks (USPs) in China and to discuss the roles of government-driven science and technology (S&T) policies in the development of USPs and the future directions of these entities. Our study shows that USPs in China have undergone two development waves: The first from the late 1980s to the late 1990s, when research universities expected to directly participate in economic activities, and the second from 2000 when the Ministry of Science and Technology (MOST) and the Ministry of Education (MOE) jointly enacted the Proposed Regulation of State-level USPs Management to guide and regulate the development of USPs. The development trajectory highlights that USPs are effective platforms that link scientific research, knowledge spillovers and industrial system. However, Chinese USPs still need to confront some conundrums which may influence the processes and outcomes of UILs. Finally, we also summarize the major issues inherent in the development of USPs to guide policymakers to enact more effective policies.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.367-374
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• 2018

A trajectory-based scheduling system is proposed for air traffic management using next generation aviation data communication link. Based on the service concept of 4-dimensional trajectory data link (4DTRAD) using air traffic serveices (ATS) datalink Baseline 2, a procedure for trajectory-based operation of an en-route flight is established and described in detail. To mitigate air traffic controllers' workload which might be caused by various and complicated data utilization, a prototype of the scheduling system, which predicts the aircraft trajectory based on the flight intents received by air traffic service system and provides advisory information for air traffic control, was developed. The simulation environment for trajectory based operation was built to validate the scheduling functionality of the prototype.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.3
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• pp.82-86
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• 2014

Modern Air Traffic Management has been shifted from the conventional vector- based clearances to trajectory based operations (TBO) concept which utilizes four-dimensional trajectory based on the internationally interoperable information using Globally Unique Flight Identifier (GUFI). This study reviews the development for TBO-related standards and Flight Information Exchange Model (FIXM), which has been discussed by the ICAO Air Traffic Management Requirements and Performance Panel (ATMRPP). In addition, plans for the next step with TBO and the Republic of Korea's participation on the Mini-Global Demonstration were also introduced.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.1036-1042
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• 2013

In this paper, an elderly assistance system is developed based on Xenomai, a real-time development framework cooperating with the Linux kernel. A Kinect sensor is used to recognize the behavior of the elderly and A-star search algorithm is implemented to find the shortest path to the person. The mobile robot also generates a trajectory using a digital convolution operator which is based on a Bezier curve for smooth driving. In order to follow the generated trajectory within the control period, we developed real-time tasks and compared the performance of the tracking trajectory with that of non real-time tasks. The real-time task has a better result on following the trajectory within the physical constraints which means that it is more appropriate to apply to an elderly assistant system.

• Journal of Family Relations
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• v.23 no.1
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• pp.75-95
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• 2018

Objectives: This study aims to examine a school adjustment trajectory of adolescents from continued single parent families and its associated factors by comparing it to that of adolescents of two-parent families. Methods: We selected 4th grade students from Korean Youth & Youth Panel Survey (KCYPS). Using a multi-level growth modeling, we followed the trajectory of school adjustment until 9th grade and the effects of family income, parenting styles, and academic motivations of adolescents on the intercepts and the slopes. Results: Adolescents' school adjustment were decreased from 4th grade to 7th grade and then increased from 7th to 9th grade. The adolescents of continued single parent families showed a lower school adjustment than those of two parent families and this trend remained constant during the period. The effects of family income, parenting style, and academic motivation were confirmed to explain the gap between the adolescents of single parent and two parent families. Conclusions: The results imply that an earlier intervention is necessary to reduce the gap. We need to offer income support and decent quality of work for single parent family to reduce the economic hardship and also provide parental education that is designed to enhance academic expectations and motivations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.183-189
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• 2009

Recently, PCS, PDA and mobile devices, such as the proliferation of spread, GPS (Global Positioning System) the use of, the rapid development of wireless network and a regular user even images, audio, video, multimedia data, such as increased use is for. In particular, video data among multimedia data, unlike the moving object, text or image data that contains information about the movements and changes in the space of time, depending on the kinds of changes that have sigongganjeok attributes. Spatial location of objects on the flow of time, changing according to the moving object (Moving Object) of the continuous movement trajectory of the meeting is called, from the user from the database that contains a given query trajectory and data trajectory similar to the finding of similar trajectory Search (Similar Sub-trajectory Retrieval) is called. To search for the trajectory, and these variations, and given the similar trajectory of the user query (Tolerance) in the search for a similar trajectory to approximate data matching (Approximate Matching) should be available. In addition, a large multimedia data from the database that you only want to be able to find a faster time-effective ways to search different from the existing research is required. To this end, in this paper effectively divided into a grid to search for the trajectory to the trajectory of moving objects, similar to the effective support of the search trajectory offers a new grid-based search techniques.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.912-915
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• 1996

The computed-torque method (CTM) shows good trajectory tracking performance in controlling robot manipulator if there is no disturbance or modelling errors. But with the increase of a payload or the disturbance of a manipulator, the tracking errors become large. So there have been many researches to reduce the tracking error. In this paper, we propose a new control algorithm based on the CTM that decreases a tracking error by generating new reference trajectory to the controller. In this algorithm we used the concept of sliding mode theory and fuzzy system to reduce chattering in control input. For the numerical simulation, we used a 2-link robot manipulator. To simulate the disturbance due to a modelling uncertainty, we added errors to each elements of the inertia matrix and the nonlinear terms and assumed a payload to the end-effector. In this simulation, proposed method showed better trajectory tracking performance compared with the CTM.

• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1159-1168
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• 2006

In this paper, a new revolute mobile robot arm with five degree of freedom (d.o.f) was developed for autonomous moving robots. As a control system for the robot arm, a distributed control system composed of the main controller and five motor controllers for arm joints was developed. The main controller and the motor controllers w ε re developed using the ARM microprocessor and the TMS320c2407 microprocessor, respectively. A new trajectory tracking algorithm for the motor controllers was devised employing pre-generated off-line trajectory data. Also, a 3-D simulator based on the openGL software to simulate the motion of the robot arm was developed. To validate the performance of the robot system, experiments to track a specified trajectory were performed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.1
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• pp.1-8
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• 2022

This study proposes a penetration model in soil considering the wake separation and reattachment based on the integrated force law (IFL). Rigid body dynamics, the IFL, and semi-empirical resistance function about soil are utilized to formulate the motion of the hard projectile. The model can predict the trajectory in soil considering the spherical cavity expansion phenomenon under various oblique angles and angles of attack (AOA). The Mohr-Coulomb yield model is utilized as the resistance function of the soil. To confirm the feasibility of the proposed model, a comparative study is conducted with experimental results described in the open literature. From the comparative study, the penetration depth estimated from the proposed model had about 13.4% error compared to that of the experimental results. In general, the finite element method is widely used to predict the trajectory in soil for a projectile. However, it takes considerable time to construct the computational model for the projectile and perform the numerical simulation. The proposed model only needs to the dimension of the projectile and can predict the trajectory of the projectile in a few seconds.