• Title/Summary/Keyword: Multiple constraints

Search Result 533, Processing Time 0.028 seconds

LINEAR POLYNOMIAL CONSTRAINTS INFERENCING ALGORITHM

  • Chi, Sung-Do
    • Journal of applied mathematics & informatics
    • /
    • v.3 no.2
    • /
    • pp.129-148
    • /
    • 1996
  • This paper propose the inference mechanism for handling linear polynomial constraints called consistency checking algorithm based on the feasibility checking algorithm borrowed from linear pro-gramming. in contrast with other approaches proposed algorithm can efficiently and coherented by linear polynomial forms. The developed algorithm is successfully applied to the symbolic simulation that offers a convenient means to conduct multiple simultaneous exploration of model behaviors.

Generation of an Optimal Trajectory for Rotorcraft Subject to Multiple Waypoint Constraints (다중 경로점 제한 조건하의 헬리콥터의 최적 경로 생성)

  • Choe,Gi-Yeong
    • 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.

An Optimal Power-Throughput Tradeoff Study for MIMO Fading Ad-Hoc Networks

  • Yousefi'zadeh, Homayoun;Jafarkhani, Hamid
    • Journal of Communications and Networks
    • /
    • v.12 no.4
    • /
    • pp.334-345
    • /
    • 2010
  • In this paper, we study optimal tradeoffs of achievable throughput versus consumed power in wireless ad-hoc networks formed by a collection of multiple antenna nodes. Relying on adaptive modulation and/or dynamic channel coding rate allocation techniques for multiple antenna systems, we examine the maximization of throughput under power constraints as well as the minimization of transmission power under throughput constraints. In our examination, we also consider the impacts of enforcing quality of service requirements expressed in the form of channel coding block loss constraints. In order to properly model temporally correlated loss observed in fading wireless channels, we propose the use of finite-state Markov chains. Details of fading statistics of signal-to-interference-noise ratio, an important indicator of transmission quality, are presented. Further, we objectively inspect complexity versus accuracy tradeoff of solving our proposed optimization problems at a global as oppose to a local topology level. Our numerical simulations profile and compare the performance of a variety of scenarios for a number of sample network topologies.

Survey of research on the optimal design of sea harbours

  • Diab, Hassan;Younes, Rafic;Lafon, Pascal
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.9 no.4
    • /
    • pp.460-472
    • /
    • 2017
  • The design of harbours, as with any other system design, must be an optimization process. In this study, a global examination of the different constraints in coastal engineering was performed and an optimization problem was defined. The problem has multiple objectives, and the criteria to be minimized are the structure cost and wave height disturbance inside a harbour. As concluded in this survey, the constraints are predefined parameters, mandatory constraints or optional constraints. All of these constraints are categorized into four categories: environmental, fluid mechanical, structural and manoeuvring.

Trajectory Planning of Satellite Formation Flying using Nonlinear Programming and Collocation

  • Lim, Hyung-Chu;Bang, Hyo-Choong
    • Journal of Astronomy and Space Sciences
    • /
    • v.25 no.4
    • /
    • pp.361-374
    • /
    • 2008
  • Recently, satellite formation flying has been a topic of significant research interest in aerospace society because it provides potential benefits compared to a large spacecraft. Some techniques have been proposed to design optimal formation trajectories minimizing fuel consumption in the process of formation configuration or reconfiguration. In this study, a method is introduced to build fuel-optimal trajectories minimizing a cost function that combines the total fuel consumption of all satellites and assignment of fuel consumption rate for each satellite. This approach is based on collocation and nonlinear programming to solve constraints for collision avoidance and the final configuration. New constraints of nonlinear equality or inequality are derived for final configuration, and nonlinear inequality constraints are established for collision avoidance. The final configuration constraints are that three or more satellites should form a projected circular orbit and make an equilateral polygon in the horizontal plane. Example scenarios, including these constraints and the cost function, are simulated by the method to generate optimal trajectories for the formation configuration and reconfiguration of multiple satellites.

Development of Multi-body Dynamics Analysis Program with Constraints using CFEM (CFEM을 이용한 구속조건이 있는 다물체 운동해석 프로그램 개발)

  • Park, Sun-Ho;Lee, Seung-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.40 no.2
    • /
    • pp.101-107
    • /
    • 2012
  • In this study, Constraint Force Equation Methodology (CFEM) is used to develop a multi-body dynamic analysis program with constraints. Seven constraint models are implemented to analyze constraint motions of multiple bodies. The augmented equations with the constraints are solved with the 4th order Runge-Kutta method for higher degree of accuracy. The analysis code is verified by comparing the analysis results of the motion of bodies with various constraints to published results.

A Representation of Engineering Change Objects and Their Integrity Constraints Using an Active Object-Oriented Database Model (능동형 객체지향적 데이터베이스 모텔을 이용한 설계변경 개체 및 제약조건의 표현)

  • 도남철
    • Journal of Information Technology Applications and Management
    • /
    • v.10 no.1
    • /
    • pp.111-125
    • /
    • 2003
  • This paper proposes a product data model that can express and enforce integrity constraints on product structure during engineering changes (ECs). The model adopts and extends an active object-oriented database model in order to Integrate IC data and their integrity constraints. Tightly integrated with product structure, It will enable designers to maintain and exchange consistent EC data throughout the product life cycle. In order to properly support operations for ECs, the model provides the data, operations, and Event-Condition-Action rules for nested ECs and simultaneous EC applications to multiple options. in addition, the EC objects proposed In the model integrate the data and Integrity constraints into a unified repository. This repository enables designers to access all EC data and integrity constraints through the product structure and relationships between EC objects. This paper also describes a prototype product data management system based on the proposed model In order to demonstrate its effectiveness.

  • PDF

Optimal Period and Priority Assignment Using Task & Message-based Scheduling in Distributed Control Systems

  • Kim, Hyoung-Yuk;Park, Hong-Seong
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2001.10a
    • /
    • pp.60.1-60
    • /
    • 2001
  • In recent years, distributed control systems(DCS) using fieldbus such as CAN have been being applied to process systems but it is very difficult to design the DCS in order to guarantee the given end-to-end constraints such as precedence constraints, time constraints, and periods and priorities of tasks and messages. This paper presents a scheduling method to guarantee the given end-to-end constraints. The presented scheduling method is the integrated one considering both tasks executed in each node and messages transmitted via the network and is designed to be applied to a general DCS that has multiple loops with several types of constraints, where each loop consists of ...

  • PDF

Truss Size Optimization with Frequency Constraints using ACO Algorithm (개미군락 최적화 알고리즘을 이용한 진동수 구속조건을 가진 트러스구조물의 크기최적화)

  • Lee, Sang-Jin;Bae, Jungeun
    • Journal of the Architectural Institute of Korea Structure & Construction
    • /
    • v.35 no.10
    • /
    • pp.135-142
    • /
    • 2019
  • Ant colony optimization(ACO) technique is utilized in truss size optimization with frequency constraints. Total weight of truss to be minimized is considered as the objective function and multiple natural frequencies are adopted as constraints. The modified traveling salesman problem(TSP) is adopted and total length of the TSP tour is interpreted as the weight of the structure. The present ACO-based design optimization procedure uses discrete design variables and the penalty function is introduced to enforce design constraints during optimization process. Three numerical examples are carried out to verify the capability of ACO in truss optimization with frequency constraints. From numerical results, the present ACO is a very effective way of finding optimum design of truss structures in free vibration. Finally, we provide the present numerical results as future reference solutions.

Scheduling of Machining Shop Composed of Machining Center and Multiple Pallets (머시닝 센터와 다연 Pallet으로 구성된 기계 가공 공장의 일정계획)

  • Lee, Cheol-Soo;Bae, Sang-Yun
    • IE interfaces
    • /
    • v.7 no.2
    • /
    • pp.107-120
    • /
    • 1994
  • This study introduces a scheduling policy to achieve unmanned operations in machining shops representing the feature of both FMS and machining centers. The proposed policy considers the practical constraints in the machining shops such as lot sizes, multiple pallets, and jig/fixtures. In addition, rescheduling to cope with extraordinary events(eg., arrival of high-priority jobs and breakdown of machines) is included. Basically, the scheduling policy consists of four procedures; (1) selection of a job according to dispatching rule, (2) selection of a machine, (3) assignment of jobs to a multiple pallet for the unmanned operation during a certain shift, and (4) prevention of unexpected machine idle caused by constraints on jig/fixture.

  • PDF