• Journal of Institute of Control, Robotics and Systems
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• v.14 no.12
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• pp.1212-1217
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• 2008

This paper studies the feasibility of using the nonlinear model predictive control as a formation flight control algorithm for unmanned aerial vehicles. The optimal control inputs for formation flight are calculated through the cost function which incorporates the relative positions of the individual vehicles to maintain a desired formation and also the inequality constraints on inputs and states using the Karush-Kuhn-Tucker conditions. In the nonlinear model predictive control setting, the optimal control inputs are implemented in a receding horizon manner, which is suitable for dealing with dynamic constraints. Numerical simulations are executed for the validation of the proposed scheme.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.10
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• pp.584-592
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• 2003

This paper presents a fuzzy-GA method for the allocation and operation of dispersed generator systems(DGs) based on load model in composite distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The problem formulation considers an objective to reduce power loss of distribution systems and the constraints such as the number or total capacity of DGs and the deviation of the bus voltage. The main idea of solving fuzzy goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm. The method proposed is applied to IEEE 12 bus and 33 bus test systems to demonstrate its effectiveness. .

• Journal of Communications and Networks
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• v.12 no.1
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• pp.30-42
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• 2010

In this work we consider the problem of downlink resource allocation for proportional fairness of long term received rates of data users and quality of service for real time sessions in an OFDMA-based wireless system. The base station allocates available power and subchannels to individual users based on long term average received rates, quality of service (QoS) based rate constraints and channel conditions. We formulate and solve a joint bandwidth and power optimization problem, solving which provides a performance improvement with respect to existing resource allocation algorithms. We propose schemes for flat as well as frequency selective fading cases. Numerical evaluation results show that the proposed method provides better QoS to voice and video sessions while providing more and fair rates to data users in comparison with existing schemes.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.5
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• pp.497-504
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• 2006

This paper presents a new technique that derives the dynamic acceleration bounds of multiple cooperating robot systems from given individual torque limits of robots. A set of linear algebraic homogeneous equation is derived from the dynamic equations of multiple robots with friction contacts. The mobility of the robot system is analyzed by the decomposition of the null space of the linear algebraic equation. The acceleration bounds of multiple robot systems are obtained from the joint torque constraints of robots by the medium of the decomposed null space. As the joint constraints of the robots are given in the infinite norm sense, the resultant acceleration bounds of the systems are described as polytopes. Several case studies are presented to validate the proposed method in this paper.

• Journal of Aerospace System Engineering
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• v.14 no.6
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• pp.1-9
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• 2020

Global e-commerce and delivery companies are actively pursuing last-mile delivery service using drones, and various delivery schedule planning studies have been conducted. In this study, separate individual route networks were constructed to reflect drone route constraints such as prohibited airspace and truck route constraints such as rivers, which previous studies did not incorporate. The A* algorithm was used to calculate the shortest path distance matrix between the starting point and destinations. In addition, we proposed an optimal delivery schedule plan using genetic algorithms and applied it to compare the efficiency with that of vehicle-only delivery.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.467-472
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• 2010

Individual vacuum pressure method is soft ground improvement technique, in which a vacuum pressure can be directly applied to the vertical drain board to promote consolidation and strengthening the soft ground. This method does not require a surcharge load, different to embankment or pre-loading method. In this study, given the inner displacement of the ground where the individual vacuum pressure is applied, this dissertation aimed to reproduce the state of stress in the ground that is subject to the constraints created by the depth of improvement area. Modified Cam Clay theory which made it possible to take into account the isotropic displacement of the ground was applied to the NAP-IVP used simulation; the conception of equivalent permeability proposed by Hird was also applied so that the 3-dimensional real construction effect of drain materials could be reflected in the analysis.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.567-579
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• 2017

The purpose of this study was conducted to clarify physical activity university students on time perspective in leisure constraints and leisure flow. To achieve this purpose, subjects of this study were sampled 295 Physical Activity University Students participant using purposeful sampling method for 2 months from May to June of 2017. Using questionnaires stratified cluster random sampling in university students in D city and C city. The analysis method was used t-test, one-way ANOVA, multiple regression analysis, correlation analysis methods in order to solve problems of the study. According to the study Result, First, studies show that female have high levels of leisure constraints than males. Males have higher levels of leisure flow than females. The first grader show high level of individual constraints and past negation were also high. In the series of majors, natural affiliates and humanities are high in the past negation, present destiny, the service major currently high in pleasure and of leisure, autotelic experience of leisure flow. In the rhythmic type of Activity type, the past negation, present destiny and leisure constraints are highly likely to be higher. In the competitive have shown that is high. Second, leisure constraints on students' participation in physical activities have been found to have negative influence on their students. Third, leisure flow have shown that they have a positive effect on past affirmation and present pleasure.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.122-134
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• 1994

Design of a heuristic algorithm for high level synthesis of multichip architecture is presented in this paper. Considering the design constraints: individual chip area, I/O pin counts, chip-to-chip interconnection counts, interchip communication delay, and chip latecy, the proposed system automatically generates pipelined multichip architectures from behavioral descriptions. For efficient mulichip synthesis, a new methodology is proposed, which performs partitioning and schedulting of SFG into multichip architectures simultaneously. Experimental results for several benchmark programs show that the systems can be used for designing multichip hardware efficiently.

• Korean Management Science Review
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• v.11 no.3
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• pp.87-102
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• 1994

Conceptual database design is an important activity because the performance of a DBMS heavily depends on the proper design of the database, and view integration is one of the most important phases of conceptual database design. During this phase, the individual views designed by separate user groups are integrated into a global view for the entire system. After the view integration, a database schema must be validated before it becomes a stable product of the design. In this paper, a methodology for view integration an validation is suggested. The individual views are modeled by entity-relationship model. The entities are integrated according to their name and domain information. After that, the relationships are merged by their constraints. We also present a methodology for checking redundant relationships which has an algorithmic description.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.6
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• pp.2217-2229
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• 2015

Since the variations of illumination, the irregular changes of human shapes, and the partial occlusions, multiple person tracking is a challenging work in computer vision. In this paper, we propose a graph clustering method based on spatio-temporal information of moving objects for multiple person tracking. First, the part-based model is utilized to localize individual foreground regions in each frame. Then, we heuristically leverage the spatio-temporal constraints to generate a set of reliable tracklets. Finally, the graph shift method is applied to handle tracklet association problem and consequently generate the completed trajectory for individual object. The extensive comparison experiments demonstrate the superiority of the proposed method.