• Journal of Digital Contents Society
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• v.8 no.4
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• pp.441-449
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• 2007

In video coding, motion estimation is a process to estimate the pixel of the current frame from the reference frame, which affects directly the predictive quality and the encoding time. This paper is related to AHHS(Adaptive Hierarchical Hexagon Search) using spatio-temporal motion activity for fast motion estimation. The proposed method defines the spatio-temporal motion activity of the current macroblock using the motion vectors of its spatio-temporally adjacent macroblocks, and then conventional AHS(Adaptive Hexagon Search) is performed if the spatio-temporal motion activity is lower, otherwise, hierarchical hexagon search is performed on a multi-layered hierarchical space constructed by multiple sub-images with low frequency in wavelet transform. In the paper, based on computer simulation results for multiple video sequences with different motion characteristics, the performance of the proposed method was analysed and assessed in terms of the predictive quality and the computational time. Experimental results indicate that the proposed method is both suitable for (quasi-) stationary and large motion searches. The proposed method could keep the merit of the adaptive hexagon search capable of fast estimating motion vectors and also adaptively reduce the local minima occurred in the video sequences with higher spatio-temporal motion activity.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.528-543
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• 2005

Statement of problem: Repeated delivery and removal of abutment cause some changes such as wear, scratch or defect of hexagonal structure. It may increase the value of rotational freedom(RF) between hexagonal structures. Purpose: The purpose of this study was to evaluate surface changes and rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment after repeated delivery and removal under SEM and toolmaker's microscope. Materials and methods: Implant systems used for this study were 3i and Avana. Seven pail's of implant fixture, abutment and abutment screws for each system were selected and all fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. Each one was embedded beneath the platform of fixture. Surfaces of hexagonal structure before repeated closing and opening of abutment were observed using SEM and rotational freedom was measured by using toolmaker's microscope. Each abutment was secured to the implant future by each abutment screw with recommended torque value using a digital torque controller and was repeatedly delivered and removed by 20 times respectively. After experiment, evaluation for the change of hexagonal structures and measurement of rotational freedom were performed. Result : The results were as follows; 1. Wear of contact area between implant fixture and abutment was considerable in both 3i and Avana system. Scratches and defects were frequently observed at the line-angle of hexagonal structures of implant fixture and abutment. 2. In the SEM view of the external hexagon of implant fixture, the point-angle areas at the corner edge of hexagon were severely worn out in both systems. It was more notable in the case of 3i systems than in that of Avana systems. 3. In the SEM view of the internal hexagon of abutment, Gingi-Hue abutment of 3i systems showed severe wear in micro-stop contacts that were machined into the corners to prevent rotation and cemented abutment of Avana systems showed wear in both surface area adjacent to the corner mating with external hexagon of implant fixture. 4 The mean values of rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment were 0.48$\pm$0.04$^{\circ}$ in pre-tested 3i systems and 1.18$\pm$0.25$^{\circ}$ after test, and 1.80$\pm$0.04$^{\circ}$ in pre-tested Avana systems and 2.61$\pm$0.16$^{\circ}$ after test. 5. Changes of rotational freedom after test shouted statistical)y a significant increase in both 3i and Avana systems(P<0.05, paired t-test). 6. Statistically, there was no significant difference between amount of increase in the rotational freedom of 3i systems and amount of increase in that of Avana ones(P>0.05, unpaired t-test). Conclusion: Conclusively, it was considered that repeated delivery and remove of abutment by 20 times would not have influence on screw joint stability. However, it caused statistically the significant change of rotational freedom in tested systems. Therefore, it is suggested that repeated delivery and remove of abutment should be minimal as possible as it could be and be done carefully Additionally, it is suggested that the means or treatment to prevent the wear of mating components should be devised.

• Journal of Digital Contents Society
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• v.9 no.2
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• pp.305-315
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• 2008

Pre-proposed AHHS(Adaptive Hierarchical Hexagon Search) is a kind of the fast hierarchical block matching algorithm based on the AHS(Adaptive Hexagon Search). It is characterized as keeping the merits of the AHS capable of fast estimating motion vectors and also adaptively reducing the local minima often occurred in the video sequences with higher spatio-temporal motion activity. The objective of this paper is to propose the method effectively extending the horizontal biased pattern and the vertical biased pattern of the AHHS to improve its predictive image quality. In the paper, based on computer simulation results for multiple video sequences with different motion characteristics, the performance of the proposed method was analysed and assessed in terms of the predictive image quality and the computational time. The simulation results indicated that the proposed method was both suitable for (quasi-) stationary and large motion searches. While the proposed method increased the computational load on the process extending the hexagon search patterns, it could improve the predictive image quality so as to cancel out the increase of the computational load.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.57-65
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• 2007

In the fast block matching algorithm. search patterns of different shapes or sizes and the distribution of motion vectors have a large impact on both the searching speed and the image qualify. In this paper, we propose a new fast block matching algorithm using the flat-hexagon search pattern that ate solved disadvantages of the diamond pattern search algorithm(DS) and the hexagon-based search algorithm(HEXBS). Our proposed algorithm finds mainly the motion vectors that not close to the center of search window using the flat-hexagon search pattern. Through experiments, compared with the DS and HEXBS, the proposed f)at-hexagon search algorithm(FHS) improves about $0.4{\sim}21.3%$ in terms of average number of search point per motion vector estimation and improves about $0.009{\sim}0.531dB$ in terms of PSNR(Peak Signal to Noise Ratio).

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.309-317
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• 2002

Line Balancing is the method enflowing workparts smoothly by balancing the worktime of processes, and reduces the cycle time. Soccer is the sports attacking the opposite team and defending a friendly area efficiently by means of ball. To accomplish this purpose, space balancing is the necessary condition. Soccer 'system' what we called 'formation' is the basic frame to balance the space of playground, operate the tactics. This paper introduces 'Dual Hexagon System', a quite new system in soccer, using line balancing principle. It also explains the correlations between line balancing and dual hexagon system, distinctions and position names of dual hexagon system, and then suggests success factors.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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• pp.445-450
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• 2009

This paper presents a new mobile robot localization method for indoor robot navigation. The method uses hexagon distributed color-coded patches on the ceiling and a camera is installed on the robot facing the ceiling to recognize these patches. The proposed "cell-coded map", with the use of only seven different kinds of color-coded landmarks distributed in hexagonal way, helps reduce the complexity of the landmark structure and the error of landmark recognition. This technique is applicable for navigation in an unlimited size of indoor space. The structure of the landmarks and the recognition method are introduced. And 2 rigid rules are also used to ensure the correctness of the recognition. Experimental results prove that the method is useful.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.171-178
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• 1998

This paper proposes a new overmodulation strategy to give a better voltage utilization by tracking voltage vector along hexagon sides. This strategy enables the inverter to control both magnitude and angle of current. Therefore, the vector control using this strategy can lead to better output torque dynamics compared to the conventional slip frequency control with six-step voltage, which is widely used in the traction drive. In this strategy, the d-axis output voltage of a current controller to control the flux is conserved and the q-axis output voltage to control the torque is controlled to place the voltage vector on the hexagon boundary In case of overmodulation. The limited q-axis voltage is used for anti-windup of q-axis current controller. This paper also presents a new field weakening scheme which incorporate the proposed overmodulation strategy. In this scheme, the flux level is selected by both required current limit and the available maximum voltage along hexagon sides. The validity of the proposed overall scheme is confirmed by the computer simulations for a typical traction drive with a 210[㎾] induction motor.

• Journal of the Korea Society of Computer and Information
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• v.23 no.9
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• pp.43-50
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• 2018

In this paper, we propose a hexagon model-based efficient beacon frame scheduling approach for wireless sensor networks. The existing beacon frame scheduling approaches use a lot of slots and subslots for the beacon frame scheduling. Thus, the data from source nodes are not efficiently delivered to a sink node. Also in case a sink node needs to broadcast a beacon frame to the nodes in the network, delivering the beacon frame to the network nodes is not efficient as well. Thus, to solve the problem, we use a hexagon model to find the number of slots and subslots for the beacon frame scheduling. By using them for the beacon frame scheduling, the proposed approach performs better than other approaches in terms of the data transmission delay, the number of received data, the beacon transmission delay and the number of relaying the beacon frames.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.141-144
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• 2003

가장 최근의 동영상 압축 표준인 H.264는 매크로블록의 최적 모드를 결정하기 위하여 총 7가지 모드를 사용하여 움직임 예측을 수행하기 때문에 부호화 효율과 수행 성능 면에서 기존의 방식에 비해 좋은 결과를 보이지만, 움직임 예측 과정에서 많은 계산 시간을 필요로 한다는 것이 커다란 단점으로 지적되고 있다. 따라서, 본 논문에서는 H.264에서 가변 블륵 단위의 움직임 예측 시 인접한 블록과의 상관성을 분석하여 다음 움직임 예측 모드의 사용 여부를 결정하는 블록 병합 알고리즘을 HEXBS(Hexagon-based Search) 고속 움직임 탐색 알고리즘에 적용하여 움직임 예측 시간을 효율적으로 절약하는 방법을 제안한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1699-1708
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• 2013

A Korean Retail Company 'Homeplus' has accomplished great growth in a short period. The main factor behind it, which is Hexagon leadership, is based on the manager's experience and management philosophy. It focuses on leaders and the ability to build basic traits of leaders. The main points are organization managing foundations such as people, work, performance, management, facilitation, training and growth. It also includes specific analysis that are applicable right away on success, failure, efficiency and effectiveness of management. The important factor for hexagon leadership is that it focuses on traits of leaders than the skills. Through training, the members of the organization can internalize the six fundamentals, which create a synergy when performed together. Positive results can be found from 'Viewpoint', which is the evaluation method of the Homeplus.