• Title/Summary/Keyword: constraint feasibility

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Processing Three Types of Korean Cleft Constructions in a Typed Feature Structure Grammar (유형화된 자질문법에서의 한국어 분열구문의 전산학적 처리)

  • Kim, Jong-Bok;Yang, Jae-Hyung
    • Korean Journal of Cognitive Science
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    • v.20 no.1
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    • pp.1-28
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    • 2009
  • The expression KES, one of the most commonly used words in the Korean language, has various usages. This expression is also used to express English-like cleft constructions. Korean seems to employ at least three different types of cleft constructions: predicational, identificational, and eventual. The paper tries to provide a constraint-based analysis of these three types of Korean cleft constructions and implement the analysis in the LKB(Linguistic Knowledge Building) system to check the feasibility of the analysis. In particular, the paper shows how a typed feature structure grammar, couched upon HPSG, can provide a robust basis for parsing Korean cleft constructions.

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Simplified Controller Design Method for Digitally Controlled LCL-Type PWM Converter with Multi-resonant Quasi-PR Controller and Capacitor-Current-Feedback Active Damping

  • Lyu, Yongcan;Lin, Hua
    • Journal of Power Electronics
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    • v.14 no.6
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    • pp.1322-1333
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    • 2014
  • To track the sinusoidal current under stationary frame and suppress the effects of low-order grid harmonics, the multi-resonant quasi-proportional plus resonant (PR) controller has been extensively used for digitally controlled LCL-type pulse-width modulation (PWM) converters with capacitor-current-feedback active damping. However, designing the controller is difficult because of its high order and large number of parameters. Moreover, the computation and PWM delays of the digitally controlled system significantly affect damping performance. In this study, the delay effect is analyzed by using the Nyquist diagrams and the system stability constraint condition can be obtained based on the Nyquist stability criterion. Moreover, impact analysis of the control parameters on the current loop performance, that is, steady-state error and stability margin, identifies that different control parameters play different decisive roles in current loop performance. Based on the analysis, a simplified controller design method based on the system specifications is proposed. Following the method, two design examples are given, and the experimental results verify the practicability and feasibility of the proposed design method.

A pilot study on the radio flux variability of dwarf galaxies

  • Hwang, Ji-Hye;Woo, Jon-Hak;Jung, Taehyun;Chung, Aeree;Trippe, Sascha;Baek, Junhyun;Lee, Taeseok;Park, Dawoo
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.2
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    • pp.71.1-71.1
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    • 2014
  • The black hole occupation fraction in dwarf galaxies can provide an important clue for understanding the black hole seed formation. As a pilot feasibility study, we performed a KVN radio monitoring campaign over 8 months for 4 dwarf galaxies. Two galaxies (IC10 and NGC1569) are detected at 22 GHz, respectively with 39 mJy, 83 mJy. The measured flux (rms) variability is 13% and 8%, respectively for IC10 and NGC1569, while the mean flux uncertainty is 25% and 12%. Thus, the detection of the radio flux variability is at best marginal. Detecting flux variability of faint sources (i.e., 22 GHz flux < 200 mJy) seems challenging with the KVN single dishes. Combining with the 1.4 GHz flux measurements from the NVSS, we find that these two galaxies have a steep spectrum, supporting that the radio sources are AGNs. Instead of a monitoring, single-epoch multi-band observations can be effective for identifying radio AGNs by providing the constraint of the radio continuum slope.

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Optimal Connection Algorithm of Two Kinds of Parts to Pairs using Hopfield Network (Hopfield Network를 이용한 이종 부품 결합의 최적화 알고리즘)

  • 오제휘;차영엽;고경용
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.2
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    • pp.174-179
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    • 1999
  • In this paper, we propose an optimal algorithm for finding the shortest connection of two kinds of parts to pairs. If total part numbers are of size N, then there are order 2ㆍ(N/2)$^{N}$ possible solutions, of which we want the one that minimizes the energy function. The appropriate dynamic rule and parameters used in network are proposed by a new energy function which is minimized when 3-constraints are satisfied. This dynamic nile has three important parameters, an enhancement variable connected to pairs, a normalized distance term and a time variable. The enhancement variable connected to pairs have to a perfect connection of two kinds of parts to pairs. The normalized distance term get rids of a unstable states caused by the change of total part numbers. And the time variable removes the un-optimal connection in the case of distance constraint and the wrong or not connection of two kinds of parts to pairs. First of all, we review the theoretical basis for Hopfield model and present a new energy function. Then, the connection matrix and the offset bias created by a new energy function and used in dynamic nile are shown. Finally, we show examples through computer simulation with 20, 30 and 40 parts and discuss the stability and feasibility of the resultant solutions for the proposed connection algorithm.m.

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A study on the treatment of a max-value cost function in parametric optimization (매개변수 종속 최적화에서 최대치형 목적함수 처리에 관한 연구)

  • Kim, Min-Soo;Choi, Dong-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.10
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    • pp.1561-1570
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    • 1997
  • This study explores the treatment of the max-value cost function over a parameter interval in parametric optimization. To avoid the computational burden of the transformation treatment using an artificial variable, a direct treatment of the original max-value cost function is proposed. It is theoretically shown that the transformation treatment results in demanding an additional equality constraint of dual variables as a part of the Kuhn-Tucker necessary conditions. Also, it is demonstrated that the usability and feasibility conditions on the search direction of the transformation treatment retard convergence rate. To investigate numerical performances of both treatments, typical optimization algorithms in ADS are employed to solve a min-max steady-state response optimization. All the algorithm tested reveal that the suggested direct treatment is more efficient and stable than the transformation treatment. Also, the better performing of the direct treatment over the transformation treatment is clearly shown by constrasting the convergence paths in the design space of the sample problem. Six min-max transient response optimization problems are also solved by using both treatments, and the comparisons of the results confirm that the performances of the direct treatment is better than those of the tranformation treatment.

An integrated particle swarm optimizer for optimization of truss structures with discrete variables

  • Mortazavi, Ali;Togan, Vedat;Nuhoglu, Ayhan
    • Structural Engineering and Mechanics
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    • v.61 no.3
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    • pp.359-370
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    • 2017
  • This study presents a particle swarm optimization algorithm integrated with weighted particle concept and improved fly-back technique. The rationale behind this integration is to utilize the affirmative properties of these new terms to improve the search capability of the standard particle swarm optimizer. Improved fly-back technique introduced in this study can be a proper alternative for widely used penalty functions to handle existing constraints. This technique emphasizes the role of the weighted particle on escaping from trapping into local optimum(s) by utilizing a recursive procedure. On the other hand, it guaranties the feasibility of the final solution by rejecting infeasible solutions throughout the optimization process. Additionally, in contrast with penalty method, the improved fly-back technique does not contain any adjustable terms, thus it does not inflict any extra ad hoc parameters to the main optimizer algorithm. The improved fly-back approach, as independent unit, can easily be integrated with other optimizers to handle the constraints. Consequently, to evaluate the performance of the proposed method on solving the truss weight minimization problems with discrete variables, several benchmark examples taken from the technical literature are examined using the presented method. The results obtained are comparatively reported through proper graphs and tables. Based on the results acquired in this study, it can be stated that the proposed method (integrated particle swarm optimizer, iPSO) is competitive with other metaheuristic algorithms in solving this class of truss optimization problems.

Analysis of 3D integral imaging systems under fixed resource constraints (제안된 리소스에서 3D 집적 영상 시스템의 분석 기법)

  • Shin, Donghak;Hong, Seok-Min;Lee, Byung-Gook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.1012-1014
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    • 2012
  • Integral imaging is considered as a next-generation 3D display which can display 3d imaging in space using lens array. The performance of integral imaging systems depends on several factors including display panel, lens array, imaging devices and so on. In this paper, we develop a unifying framework to evaluate the resolution of integral imaging systems under fixed resource constraints. The proposed framework enables one to optimize the system performance. To show the feasibility of the proposed method, we carry out Monte Carlo simulations based on this framework and present the results.

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MODIFIED DOUBLE SNAKE ALGORITHM FOR ROAD FEATURE UPDATING OF DIGITAL MAPS USING QUICKBIRD IMAGERY

  • Choi, Jae-Wan;Kim, Hye-Jin;Byun, Young-Gi;Han, You-Kyung;Kim, Yong-Il
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.234-237
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    • 2007
  • Road networks are important geospatial databases for various GIS (Geographic Information System) applications. Road digital maps may contain geometric spatial errors due to human and scanning errors, but manually updating roads information is time consuming. In this paper, we developed a new road features updating methodology using from multispectral high-resolution satellite image and pre-existing vector map. The approach is based on initial seed point generation using line segment matching and a modified double snake algorithm. Firstly, we conducted line segment matching between the road vector data and the edges of image obtained by Canny operator. Then, the translated road data was used to initialize the seed points of the double snake model in order to refine the updating of road features. The double snake algorithm is composed of two open snake models which are evolving jointly to keep a parallel between them. In the proposed algorithm, a new energy term was added which behaved as a constraint. It forced the snake nodes not to be out of potential road pixels in multispectral image. The experiment was accomplished using a QuickBird pan-sharpened multispectral image and 1:5,000 digital road maps of Daejeon. We showed the feasibility of the approach by presenting results in this urban area.

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Development of a Vision Sensor-based Vehicle Detection System (스테레오 비전센서를 이용한 선행차량 감지 시스템의 개발)

  • Hwang, Jun-Yeon;Hong, Dae-Gun;Huh, Kun-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.6
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    • pp.134-140
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    • 2008
  • Preceding vehicle detection is a crucial issue for driver assistance system as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision. The vision-based preceded vehicle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an preceded vehicle detection system is developed using stereo vision sensors. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the preceded vehicles including a leading vehicle. Then, the position parameters of the preceded vehicles or leading vehicles can be obtained. The proposed preceded vehicle detection system is implemented on a passenger car and its performances is verified experimentally.

Solving the Constrained Job Sequencing Problem using Candidate Order based Tabu Search (후보순위 기반 타부 서치를 이용한 제약 조건을 갖는 작업 순서결정 문제 풀이)

  • Jeong, Sung-Wook;Kim, Jun-Woo
    • The Journal of Information Systems
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    • v.25 no.1
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    • pp.159-182
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    • 2016
  • Purpose This paper aims to develop a novel tabu search algorithm for solving the sequencing problems with precedence constraints. Due to constraints, the traditional meta heuristic methods can generate infeasible solutions during search procedure, which must be carefully dealt with. On the contrary, the candidate order based tabu search (COTS) is based on a novel neighborhood structure that guarantees the feasibility of solutions, and can dealt with a wide range of sequencing problems in flexible manner. Design/methodology/approach Candidate order scheme is a strategy for constructing a feasible sequence by iteratively appending an item at a time, and it has been successfully applied to genetic algorithm. The primary benefit of the candidate order scheme is that it can effectively deal with the additional constraints of sequencing problems and always generates the feasible solutions. In this paper, the candidate order scheme is used to design the neighborhood structure, tabu list and diversification operation of tabu search. Findings The COTS has been applied to the single machine job sequencing problems, and we can see that COTS can find the good solutions whether additional constraints exist or not. Especially, the experiment results reveal that the COTS is a promising approach for solving the sequencing problems with precedence constraints. In addition, the operations of COTS are intuitive and easy to understand, and it is expected that this paper will provide useful insights into the sequencing problems to the practitioners.