• Journal of Korean Institute of Industrial Engineers
• /
• v.19 no.2
• /
• pp.3-13
• /
• 1993

In this study, we develop a B & B type algorithm for the concave minimization problem with 0-1 knapsack constraint. Our algorithm reformulates the original problem into the singly linearly constrained concave minimization problem by relaxing 0-1 integer constraint in order to get a lower bound. But this relaxed problem is the concave minimization problem known as NP-hard. Thus the linear function that underestimates the concave objective function over the given domain set is introduced. The introduction of this function bears the following important meanings. Firstly, we can efficiently calculate the lower bound of the optimal object value using the conventional convex optimization methods. Secondly, the above linear function like the concave objective function generates the vertices of the relaxed solution set of the subproblem, which is used to update the upper bound. The fact that the linear underestimating function is uniquely determined over a given simplex enables us to fix underestimating function by considering the simplex containing the relaxed solution set. The initial containing simplex that is the intersection of the linear constraint and the nonnegative orthant is sequentially partitioned into the subsimplices which are related to subproblems.

• Proceedings of the Korean Society for Language and Information Conference
• /
• 2007.11a
• /
• pp.223-233
• /
• 2007

The so-called Korean BNC (bound noun construction) displays complex syntactic, semantic, and constructional properties. This paper, couched upon a constraint-based approach, two different syntactic structures for the construction with articulated lexical properties for the BNs and relevant predicates. The paper reports an implementation of this analysis in the LKB (Linguistic Knowledge Building) system and shows us that this direction is robust enough to pare relevant sentences.

• Journal of Information Technology Applications and Management
• /
• v.22 no.2
• /
• pp.1-17
• /
• 2015

In this research, we develop and suggest branch and bound algorithms for a two-machine permutation flowshop scheduling problem with the objective of minimizing makespan. In this scheduling problem, after each job is operated on the machine 1 (first machine), the job has to start its second operation on machine 2 (second machine) within its corresponding limited waiting time. In addition, each job has its corresponding ready time at the machine 1. For this scheduling problem, we develop various dominance properties and three lower bounding schemes, which are used for the suggested branch and bound algorithm. In the results of computational tests, the branch and bound algorithms with dominance properties and lower bounding schemes, which are suggested in this paper, can give optimal solution within shorter CPU times than the branch and bound algorithms without those. Therefore, we can say that the suggested dominance properties and lower bounding schemes are efficient.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.40 no.2
• /
• pp.10-18
• /
• 2003

This paper presents a method for designing guaranteed cost fuzzy filter with a desired H$_{\infty}$ disturbance rejection constraint of delayed fuzzy dynamic systems. This method not only guarantees an induced L$_2$ norm bound constraint on disturbance attenuation, but also minimizes an upper bound on a linear quadratic performance measure. A sufficient condition for the existence of guaranteed cost fuzzy filter with H$_{\infty}$ constraint is then presented in terms of linear matrix inequalities(LMIs). A simulation example is given to illustrate the design procedures and performances of the proposed methods.

• Journal of KIISE:Software and Applications
• /
• v.37 no.7
• /
• pp.584-589
• /
• 2010

The dynamic time warping algorithm generally used in time series pattern recognition spends most of the time in generating the correlation table, and it establishes the global path constraint to reduce the corresponding time complexity. However, the constraint restrains just in terms of the time axis, not considering the contents of input patterns. In this paper, we therefore propose an efficient branch and bound dynamic time warping algorithm which sets the global constraints by adaptively reflecting the patterns. The experimental results show that the proposed method outperforms conventional methods in terms of the speed and accuracy.

• Nuclear Engineering and Technology
• /
• v.54 no.10
• /
• pp.3660-3671
• /
• 2022

A new methodology to derive a dose constraint for radioactive effluent from a unit of nuclear power plant (NPP) through retrospective assessment was developed to reflect operational flexibility in line with international standards. The new dose constraint can retain the safety margin between the offsite dose and the past dose constraints. As case studies, the new approach was applied to 24 Korean NPPs to address the limitations of the existing seven dose constraints that do not fully comply with current international radiation protection standards. Therefore, an effective dose constraint for Korean NPPs was proposed as no less than 0.15 mSv/y, which is comparable to the international practices and previous studies (0.05-0.3 mSv/y). Although the lower bound of the equivalent dose constraint was calculated as 0.17 mSv/y, it is not proposed in this study since the compliance with the derived effective dose constraint can prevent accompanied equivalent doses to any organs from exceeding equivalent dose limits. The new framework and the case studies are expected to contribute toward and support the revision of existing dose constraints for radioactive effluent from NPPs, ensuring better compliance with the current international safety standards as well as reflect the operational flexibility in practice.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.1
• /
• pp.9-12
• /
• 2005

This paper presents an LMI-based method to design sliding mode observers for a class of uncertain systems. Using LIs we derive an existence condition of a sliding mode observer guaranteeing a stable sliding motion. And we give explicit formulas of the observer gain matrices. We also consider sliding mode observer design problems under an α-stability constraint or an LQ performance bound constraint. Finally, we give a numerical design example.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.26 no.3
• /
• pp.95-104
• /
• 2001

In this paper, we consider a maximin version of the linear programming knapsack problem with extended generalized upper bound (GUB) constraints. We solve the problem efficiently by exploiting its special structure without transforming it into a standard linear programming problem. We present an O(n$^3$) algorithm for deriving the optimal solution where n is the total number of problem variables. We illustrate a numerical example.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.22 no.3
• /
• pp.1-9
• /
• 1997

We present an extension of the well-known generalized upper bound (GUB) constraint and consider a linear knapsack problem with both the extended GUB constraints and the simple upper bound (SUB) constraints. An efficient algorithm of order O($n^2log n$) is developed by exploiting structural properties and applying binary search to ordered solution sets, where n is the total number of variables. A numerical example is presented.

• Journal of Korean Institute of Industrial Engineers
• /
• v.14 no.2
• /
• pp.41-51
• /
• 1988

In this paper an efficient heuristic for the generalized assignment problem(GAP) is presented. A new lower bound that is slightly improved by adding the feasibility constraint is used to measure the quality of solutions obtained by the heuristic. The heuristic was tested on a number of large-scale random problems and a large sample of small problems. The heuristic appears to be better than the best previously existing heuristic for GAP. Its effectiveness in comparison of running times and closenesses to lower bound is discussed.