• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2873-2892
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• 2019

Reducing the interference to the licensed mobile users and obtaining the energy efficiency are key issues in cognitive heterogeneous networks. A corresponding rate loss constraint is proposed to be used for the sensing-based spectrum sharing (SBSS) model in cognitive heterogeneous networks in this paper. Resource allocation optimization strategy is designed for the maximum energy efficiency under the proposed interference constraint together with average transmission power constraint. An efficiency algorithm is studied to maximize energy efficiency due to the nonconvex optimal problem. Furthermore, the relationship between the proposed protection criterion and the conventional interference constraint strategy under imperfect sensing condition for the SBSS model is also investigated, and we found that the conventional interference threshold can be regarded as the upper bound of the maximum rate loss that the primary user could tolerate. Simulation results have shown the effectiveness of the proposed protection criterion overcome the conventional interference power constraint.

• 한국멀티미디어학회논문지
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• 제9권12호
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• pp.1560-1571
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• 2006

In order to transmit multimedia streams over the network with a timely changing channel bandwidth such as Internet, scalable video coding schemes have been studied to represent video in flexible bitstream. Much research has been made on how to represent encoded media(such as video) bitstream in scalable ways. In this paper, rte propose an optimal selection of the objects for MPEG-4 bitstream adaptation to meet a given constraint. We adopt a multiple choice knapsack problem with multi-step selection for the MPEG-4 objects with different bit-rate scaling levels in the MPEG-4 bitstream. The bitstream adaptation based on the optimal selection result is then to fetch the necessary parts of the MPEG-4 bitstream to constitute an adapted version of the original MPEG-4 binary resource. The experiment results show that the optimal selection of MPEG-4 objects for a given constraint can promisingly be made which meets the given constraint.

• 한국통신학회논문지
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• 제41권8호
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• pp.917-920
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• 2016

전통적 도래각 추정기법[1]과 별개로 2004년 이후 입사신호의 입사방향은 공간 영역에서 희소도(sparsity)를 가짐을 이용한 도래각 추정 기법이 제안되었다. 압축센싱 기반 도래각 추정 알고리즘인 SpSF 알고리즘에 이용되는 비용함수는 비선형 다변수 최적화문제이다. 적절한 변환을 통하여 해당 비용함수는 볼록 최적화 (convex optimization) 문제로 표현할 수 있다. 볼록 최적화 문제는 제한조건이 있는 최적화 문제이며 제한조건에 포함되는 상수를 지정해야 한다. 본 연구에서는 제한조건에 포함되는 사용자지정 상수값 결정법을 제안한다. 잡음의 실수부와 허수부가 서로 독립인 평균 0인 정규분포를 따름을 이용하여 제한조건에 포함되는 행렬의 Frobenius norm의 평균을 유도할 수 있으며, 이를 이용하여 제한조건에 포함되는 상수를 결정할 수 있다. 제안된 방법에 의해 결정된 상수를 이용한 SpSF 알고리즘이 실제로 동작함을 보였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.217-220
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• 2000

This paper studies a real-time VBR traffic characterization. There are two big approaches to determine traffic. One is a statistic approach and the other is a deterministic approach. This paper proposes a new constraint function, what we called “Sub-Sum Constraint Function”(SSCF). This function is mainly based on a deterministic approach and uses a statistic approach. It predicts and calculates the next rate with a present information about the stream. SSCF captures the intuitive bounded by a rate lower than its peak rate and closer to its long-term average rate. This model makes a order of the constraint function much less than any other works (O(n)). It can also be mapped on a token bucket algorithm which consists of r (token rate) and b (token depth). We use a concept, EB(effective bandwidth) for a utility of our function and comparing with other techniques such as CBR, average VBR. We simulated 21 multimedia sources for verifying the utility of our function.

• 전자공학회논문지B
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• 제29B권7호
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• pp.42-51
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• 1992

This paper suggests a measure constraint locus which is the loci of points satisfying the necessary constraint for optimality of a measure in the configuration space. The characterization of four measures for singularity avoidance is worked out by using the measure constraint locus. It gives a global look at the performance of an inverse kinematic algorithm whien each of measures in a kinematically redundant robot is used. The invertible workspace without singularities and the topological properties both on the configuration and operational spaces are analyzed. We discuss also some limitations, based on the topological arguments of measure constraint locus, of the inverse kinematic algorithms, and compare global properties of each of measure. Therfore, a new concept called measure constraint locus gives a methodology for obtaining a conservative joint trajectory without singularities for almost entire workspace.

• Journal of Welding and Joining
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• 제20권3호
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• pp.129-137
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• 2002

This study presents a new method to derive the constraint coefficient from the degree of angular deformation caused by welding, as measured experimentally by varying the shape of welded joints and the magnitude of constraints and from analysis results given by the elastic FEM method. The equivalent load was then calculated with this constraint coefficient. The validity of the numerical analysis involved in this new method was confirmed by its agreement with the experimental results. As for the effects of the constraints based on the shape of the welded joints in the case of Butt welding when the constraint coefficients are not considered, the deformed quantity produced by analysis is larger that produced by experiment and consequently is largely affected by the constraints. However, in the case of Fillet welding, the deformed quantity is seldom affected regardless of constraint coefficient considerations.

• 한국컴퓨터정보학회논문지
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• 제24권4호
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• pp.27-34
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• 2019

The course timetabling problem is a kind of very complex combinatorial optimization problems, which is known as an NP-complete problem. Sometimes a given course timetabling problem can be accompanied by many constraints. At this time, even if only one constraint is violated, it can be an infeasible timetable. Therefore, it is very difficult to make an automated course timetabling system for a complex real-world course timetabling problem. This paper introduces an automated course timetabling system using constraint programming. The target problem has 26 constraints in total, and they are expressed as 24 constraints and an objective function in constraint programming. Currently, we are making a timetable through this system and applying the result to the actual class. Members' satisfaction is also much higher than manual results. We expect this paper can be a guide for making an automated course timetabling system.

• 경영과정보연구
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• 제35권1호
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• pp.69-84
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• 2016

본 연구는 목적인 소비자의 구전제약요인과 구전과의 관계를 여가제약 이론을 바탕으로 구전제약요인들과 이에 대한 협상노력이 몰입과 구전의도와 관계를 살펴보기 위한 연구모형을 설정하였으며, 변수들 간의 관계를 실증적으로 검증하였으며, 연구결과를 요약하면 다음과 같다. 가설을 검증한 결과 2개의 가설(가설 1, 가설 5)을 제외하고 모든 가설이 채택되었다. 이에 대한 구체적인 결과는 다음과 같다. 첫 번째, 내재적제약이 구전제약 요인이 구전제약 협상노력에 미치는 영향을 살펴보면 다음과 같다. 대인적제약과 구조적제약은 구전제약 협상노력에 정(+)의 영향을 미치고 있으며, 내재적 제약의 경우 음(-)의 영향을 미치는 것으로 나타나 가설검증에서는 기각하였지만, 통계적으로는 유의한 것으로 나타났다. 두 번째, 구전제약 협상노력과 몰입 그리고 구전과의 구조적인 관계를 살펴보면 다음과 같다. 구전제약 협상노력은 몰입에 정(+)의 영향을 미치고 있지만, 구전에는 통계적으로 유의하지 않는 것으로 나타났다. 마지막으로 몰입은 구전에 정(+)의 영향을 미치는 것으로 나타나 매개역할을 하고 있음을 알 수 있다. 본 연구의 결과는 구전제약요인과 소비자의 몰입과 구전에 대한 종합적인 이해와 함께 중요한 이론적, 실무적 시사점을 제공할 것으로 기대된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.249-268
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• 2014

Relevance feedback is an effective tool to bridge the gap between superficial image contents and medically-relevant sense in content-based medical image retrieval. In this paper, we propose an interactive medical image search framework based on pairwise constraint propagation. The basic idea is to obtain pairwise constraints from user feedback and propagate them to the entire image set to reconstruct the similarity matrix, and then rank medical images on this new manifold. In contrast to most of the algorithms that only concern manifold structure, the proposed method integrates pairwise constraint information in a feedback procedure and resolves the small sample size and the asymmetrical training typically in relevance feedback. We also introduce a long-term feedback strategy for our retrieval tasks. Experiments on two medical image datasets indicate the proposed approach can significantly improve the performance of medical image retrieval. The experiments also indicate that the proposed approach outperforms previous relevance feedback models.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.1-12
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• 2009

Iterative algorithms are proposed for the least-squares symmetric solution of AXB = E with a submatrix constraint. We characterize the linear mappings from their independent element space to the constrained solution sets, study their properties and use these properties to propose two matrix iterative algorithms that can find the minimum and quasi-minimum norm solution based on the classical LSQR algorithm for solving the unconstrained LS problem. Numerical results are provided that show the efficiency of the proposed methods.