• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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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.

• 경영과정보연구
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• 제38권2호
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• pp.209-223
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• 2019

본 연구는 소셜네트워크에서 SNS 광고에 대한 구전 제약요인의 개념과 측정도구 개발을 통하여 온라인 구전을 활성화하는데 그 목적이 있다. 이런 연구 목적을 달성하기 위해 3단계의 연구를 수행하였다. 첫째, 문헌고찰과 정성적 조사방법을 통하여 구전 제약에 대한 개념과 범위에 대하여 탐색적 조사(표적 집단 면접과 심층면접, 전문가 면접)를 실시하였다. 둘째, 개발된 측정항목은 정제작업을 위해 설문 조사를 실시하여 측정문항에 대한 신뢰성과 타당성 검증을 하였다. 셋째, 개발된 측정문항과 다른 주요 구성개념과 관계를 살펴봄으로써 측정항목의 예측타당성을 검증하였다. 연구결과 6개의 구성요인과 이에 대한 총 23개의 측정문항이 도출되었으며, 각각 내재적 및 대인적 제약(심리적 민감성, 보상적 민감성, 타인평가 민감성), 구조적 제약(신뢰성, 정보성, 오락성)으로 명명하였다. 정성적 연구와 정량적 연구를 통해 구전 제약의 측정문항을 개발하였으며, SNS 성과 및 평가 측면에서 SNS 광고 구전의 제약요인으로 작용하고 있는 사회적, 심리적, 환경적인 방해 요인들을 구전 제약의 관점에서 통합적으로 살펴보았다. 본 연구를 통해 온라인 구전 제약에 대한 체계적이고 실증적인 연구수행을 위한 기본 틀과 효과적인 SNS 구전을 이끌어 낼 수 있을 것이다.

• 대한전자공학회논문지SP
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• 제40권1호
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• pp.79-86
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• 2003

본 논문에서는 블록 변화된 영상의 블록 환상을 제거하기 위해 POCS(Projection Onto Convex Set) 이론을 바탕으로 하는 적응 양자화 체한 집합을 제안한다. POCS 이론을 바탕으로 하는 블록 현상 제기 기법은 크게 부드러움 제한 집합과 양자화 제한 집합으로의 반복적인 투영을 동해 이루어진다. 기존의 양자화 제한 집합은 원 영상의 데이터가 가질 수 있는 최대 구간을 지정해 주므로 반복이 계속될수록 over-blurring 현상이 심화된다. 제안한 양자화 제한 집합은 이산 여현 변환(DCT) 계수의 특성에 파라 적응적으로 제한 구간을 조절하므로 복호화된 영상의 선명도를 유지하면서 동시에 효과적으로 블록 현상을 제거할 수 있다. 기존의 후처리 알고리즘의 양자화 제한 집합을 제안한 적응적 양자화 제한 집합으로 대체하여 실험을 수행한 결과 적은 반복 횟수로도 수령에 도달하였고 후처리 된 영상 역시 선명도를 유지하면서 블록 현상이 효과적으로 제거되었음을 알 수 있었다.

• Journal of Information Processing Systems
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• 제2권1호
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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.

• 대한임베디드공학회논문지
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• 제8권2호
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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.

• 한국컴퓨터정보학회논문지
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• 제22권9호
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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.

• 전자공학회논문지B
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• 제28B권10호
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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.

• 한국정보시스템학회지:정보시스템연구
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• 제27권4호
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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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• 제9권7호
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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.

• 대한전자공학회논문지SP
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• 제46권5호
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• pp.8-14
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• 2009

본 논문에서는, 컴프레시브 센싱(compressive sensing, CS)에서 양자화된 측정을 사용하여 CS 복구(reconstruction)를 하는 경우에 일반화된 양자화 제한(generalized quantization constraint, GQC) 집합을 사용하여 convex 최적화를 수행하는 방법을 제안하였다. 제안한 GQC에서는 기존의 양자화 제한 집합의 크기를 조정할 수 있도록 하였으며, 균일 스칼라 양자기를 사용한 CS 복구의 모의실험을 통하여 m/klogn > 2 인 CS 문제에서, 기존의 QC 방법에 비하여 CS 복구의 에러에서 3.4-3.6dB의 성능 개선을 얻을 수 있었다.