• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.6
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• pp.2044-2059
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• 2022

Recent works have shown that the geometric constraint can be harnessed to boost the performance of CNN-based camera localization. However, the existing strategies are limited to imposing image-level constraint between pose pairs, which is weak and coarse-gained. In this paper, we introduce a pixel-level epipolar geometry constraint to vanilla localization framework without the ground-truth 3D information. Dubbed EpiLoc, our method establishes the geometric relationship between pixels in different images by utilizing the epipolar geometry thus forcing the network to regress more accurate poses. We also propose a variant called EpiSingle to cope with non-sequential training images, which can construct the epipolar geometry constraint based on a single image in a self-supervised manner. Extensive experiments on the public indoor 7Scenes and outdoor RobotCar datasets show that the proposed pixel-level constraint is valuable, and helps our EpiLoc achieve state-of-the-art results in the end-to-end camera localization task.

• Management & Information Systems Review
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• v.38 no.2
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• pp.209-223
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• 2019

The purpose of this study was to stimulate the online word-of-mouth advertising by developing the concept of word-of-mouth constraint factors and measurement tools in connection with the SNS advertising on social networks. To achieve the objective of this study, this study was conducted in 3 phases. First, the exploratory investigation(target group interview, in-depth interview, and expert interview) was performed to determine the concept and scope of the word-of-mouth constraint based on literature study and qualitative investigation method. Second, the reliability and validity of the measurement questions were verified through the survey in order to refine the developed measurement items. Third, the predictive validity of measurement items was verified by examining the relationship with other major construct concept for which the developed measurement items were different. Based on the results of study, 6 components and a total of 23 measurement questions for those components were derived. Each was called intrapersonal and interpersonal constraint(psychological sensitivity, compensatory sensitivity, and other person assessment), structural constraint(reliability, informativity, and entertainment). We developed the measurement questions related to word-of-mouth constraint based on qualitative study and quantitative study and holistically examined the social and psychological, environmental interruption factors acting as the word-of-mouth constraint factors for SNS advertising in terms of SNS achievements and evaluation from the perspective of word-of-mouth constraint. The results will lead to creation of basic framework for systematic and empirical research on the online word-of-mouth constraint and to achievement of effective SNS word-of-mouth advertising.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.79-86
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• 2003

A new quantization constraint set based on the theory of Projection onto Convex Set(POCS) is proposed to reduce blocking artifact appearing in block-coded images. POCS-based postprocessing for alleviating the blocking artifact consists of iterative projections onto smoothness constraint set and quantization constraint set, respectively. In general, the conventional quantization constraint set has the maximum size of range where original image data can be included, therefore over-blurring of restored image is unavoidable as iteration proceeds. The projection onto the proposed quantization constraint set can reduce blocking artifact as well as maintain the clearness of the decoded image, since it controls adaptively the size of quantization constraint set according to the DCT coefficients. Simulation results using the proposed quantization constraint set as a substitute for conventional quantization constraint set show that the blocking artifact of the decoded image can be reduced by the small number of iterations, and we know that the postprocessed image maintains the distinction of the decoded image.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.1-5
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• 2006

Finding a valid timing constraint is one of the most important issues in the real-time monitoring area. To get the valid timing constraint, a developer executes a real-time process and changes the constraint on a regular basis. This is an exhaustive and time-consuming process. To improve this approach, we propose a timing constraint search technique. This technique uses two load models and one condition proposed in this paper to support the developer in determining the valid timing constraint range in an easy and systematic manner.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.2
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• pp.111-119
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• 2013

This paper proposes one method on photometric stereo calibration using the constraint on light source directions in which the light sources have the unknown tilt and slant angles but the slant angles are the same. First, the constraint is analyzed based on the equation of linear ambiguity which leads to the conclusion that another constraint should be added to solve the calibration completely. Later, the combination of constraint on light source directions and the constraint that there exists at least six surface patches having known albedos is exploited to resolve the linear ambiguity up to an accurate and close-form solution. The effective performance of the proposed method is demonstrated through experiment results.

• Journal of the Korea Society of Computer and Information
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• v.22 no.9
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• pp.9-16
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• 2017

The course timetabling problem is a problem assigning a set of subjects to the given classrooms and different timeslots, while satisfying various hard constraints and soft constraints. This problem is defined as a constraint satisfaction optimization problem and is known as an NP-complete problem. Various methods has been proposed such as integer programming, constraint programming and local search methods to solve a variety of course timetabling problems. In this paper, we propose an iterative improvement search method to solve the problem based on constraint programming. First, an initial solution satisfying all the hard constraints is obtained by constraint programming, and then the solution is repeatedly improved using constraint programming again by adding new constraints to improve the quality of the soft constraints. Through experimental results, we confirmed that the proposed method can find far better solutions in a shorter time than the manual method.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.10
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• pp.761-770
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• 1991

This paper suggests a measure constraint locus for characterization of the performance of a subtask for a redundant robot. The measure constraint locus are the loci of points satisfying the necessary constraint for optimality of measure in the joint configuration space. To uniquely obtain an inverse kinematic solution, one must consider both measure constraint locus and self-motion manifolds which are set of homogeneous solutions. Using measure constraint locus for maniqulability measure, the invertible workspace without singularities and the topological property of the configuration space for linding equilibrium configurations are analyzed. We discuss some limitations based on the topological arguments of measure constraint locus, of the inverse kinematic algorithm for a cyclic task. And the inverse kinematic algorithm using global maxima on self-motion manifolds is proposed and its property is studied.

• The Journal of Information Systems
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• v.27 no.4
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• pp.203-227
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• 2018

Purpose The purpose of this study is to investigate which decision factors continue to use the service based on the online simple payment service. In this study, we will examine how to activate the service from the continuing factors through the dual-model theory consisting of personal dedication and constraint dedication which are frequently used in relation marketing. Design/methodology/approach In this study, we investigated the activation of online simple settlement service using factors affecting the preference of the simple payment service based on the dual-model of dedication-based mechanism and constraint-based mechanism. Findings This study confirmed that customer satisfaction and convenience under the dedication -based mechanism were found to be linked to the preference of the simple payment service. Switching cost under the constraint - based mechanism showed that the customer had no binding ability to continue using the service of the current provider. Likewise, preference was found to have a direct effect on the actual frequency of use of the simple payment service, the number of uses compared to the total number of online payments, and willingness to use more.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2338-2353
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• 2015

In this paper, the optimal power allocation algorithm that minimizes the aggregate bit error rate (BER) of the secondary user (SU) in a downlink orthogonal frequency division multiplexing (OFDM) based cognitive radio (CR) system, while subjecting to the interference power constraint and the transmit power constraint, is investigated under the assumption that the instantaneous channel state information (CSI) of the interference links between the secondary transmitter and the primary receiver, and between the primary transmitter and the secondary receiver is perfectly known. Besides, a suboptimal algorithm with less complexity is also proposed. In order to deal with more practical situations, we further assume that only the channel distribution information (CDI) of the interference links is available and propose heuristic power allocation algorithms based on bisection search method to minimize the aggregate BER under the interference outage constraint and the transmit power constraint. Simulation results are presented to verify the effectiveness of the proposed algorithms.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.8-14
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• 2009

In this paper, a convex optimization technique, which is based on the generalized quantization constraint (GQC), is proposed in the compressive sensing reconstruction using quantized measures. The set size of the proposed GQC can be controlled, and through extensive numerical simulations based on the uniform scalar quantizers, the CS reconstruction errors are improved by 3.4-3.6dB compared to the traditional QC method for the CS problems of m/klogn > 2.