• Journal of the Korean Data and Information Science Society
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• 제21권1호
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• pp.121-128
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• 2010

케이-평균 군집분석은 데이터들을 k개의 군집으로 임의로 분할을 하여 군집의 평균을 대푯값으로 분할해 나가는 방법으로 데이터들을 유사성을 바탕으로 재배치를 하는 방법이다. 이러한 케이-평균 군집분석은 시장조사, 패턴분석 및 인식, 그리고 이미지 처리 분야 등에서 폭넓게 응용되고 있다. 그러나 대용량의 데이터베이스를 분석대상으로 하므로 그 만큼 데이터 처리 시간이 많이 소요되는 것이 문제 중의 하나이다. 특히 웹이 보편화된 현재 사용자들의 다양한 패턴을 분석하기 위한 데이터 마이닝 방법이 사용되어지고 있는데 처리 속도 문제는 더욱 중요하게 생각하고 있다. 이러한 속도 문제를 해결하기 위해 본 논문에서는 분할 군집법에서 가장 일반적으로 사용되고 있는 케이-평균 알고리즘에 대해 그리드를 기반으로 한 무게중심 알고리즘을 제안하고자 한다.

• 한국정밀공학회지
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• 제23권3호
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• pp.187-194
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• 2006

Unexpected postoperative changes, such as growth in rib hump and shoulder unbalance, have been occasionally reported after corrective surgery for scoliosis. However there has been neither experimental data fer explanation of these changes, nor the suggestion of optimal correction method. Therefore, the numerical study was designed to investigate the post-operative changes of vertebral rotation and rib cage deformation after the corrective surgery of scoliosis. A mathematical finite element model of normal spine including rib cage, sternum, both clavicles, and pelvis was developed with anatomical details. In this study, we also developed a special program which could convert a normal spine model to a desired scoliotic spine model automatically. A personalized skeletal deformity of scoliosis model was reconstructed with X-ray images of a scoliosis patient from the normal spine structures and rib cage model. The geometric mapping was performed by translating and rotating the spinal column with an amount analyzed from the digitized 12 built-in coordinate axes in each vertebral image. By utilizing this program, problems generated in mapping procedure such as facet joint overlapping, vertebral body deformity could be automatically resolved.

• International Journal of Control, Automation, and Systems
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• 제5권1호
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• pp.15-23
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• 2007

In surveillance, monitoring, and target tracking operations, high-resolution images should be obtained even if the target is in a far distance. Frequent movements of vehicles such as boats degrade the image quality of onboard camera systems. Therefore, stabilizer mechanisms are required to stabilize the line of sight of boatboard camera systems against boat movements. This paper addresses design and implementation of a strapdown boatboard camera stabilizer. A two degree of freedom(DOF)(pan/tilt) robot performs the stabilization task. The main problem is divided into two subproblems dealing with attitude estimation and attitude control. It is assumed that exact estimate of the boat movement is available from an attitude estimation system. Estimates obtained in this way are carefully transformed to robot coordinate frame to provide desired trajectories, which should be tracked by the robot to compensate for the boat movements. Such a practical robotic system includes actuators with fast dynamics(electrical dynamics) and has more degrees of freedom than control inputs. Backstepping method is employed to deal with this problem by extending the control effectiveness.

• 한국관광식음료학회지:관광식음료경영연구
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• 제10권
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• pp.109-138
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• 1999

The hotel does not sell one-time services, and the customer has many choices, especially today. And hotel is vulnerable to new competition. Most customers likes to try a new place and new product. The questions are 1) offering competitive products that are meaningful to customers 2) solving customers problems 3) offering a competitive products that are difficult for competitors to duplicate. This report is for studying about the relationship between the results of National Customer Satisfaction Index(NCSI) and the hotels' revenue. And explore the ways to identify opportunities for creating the desired image that differentiates from the competition and for serving the target market better than anyone else. For the about objectives, the following items are reviewed: 1) Customer behavior and customers' needs and wants 2) Customer decisions 3) Integrated marketing 4) Customer satisfaction 5) Major factors of the hotel customers satisfaction 6) Moment of truty Market positioning is to creat a distinctive place in the minds of potential customer. To position successfully requires recognizing the marketplaces. the competition, value for money and customers' perceptions. Finally, internal marketing efforts can be used to examine one's own position to see if it is perceived by it's customers. It means that the benefits exist in the mind of the customer and are determinable only by asking the customer. These kinds of efforts are essential to proper positioning analysis and long term relationship marketing.

• 한국정밀공학회지
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• 제26권11호
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• pp.92-98
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• 2009

The scanning electron microscope (SEM) contains an electron optical system in which electrons are emitted and moved to form a focused beam, and generates secondary electrons from the specimen surfaces, eventually making an image. The electron optical system usually contains two condenser lenses and an objective lens. The condenser lenses generate a magnetic field that forces the electron beams to form crossovers at desired locations. The objective lens then focuses the electron beams on the specimen. The present study covers the design and analysis of an objective lens for a thermionic SEM. A finite element (FE) analysis for the objective lens is performed to analyze its magnetic characteristics for various lens designs. Relevant beam trajectories are also investigated by tracing the ray path of the electron beams under the magnetic fields inside the objective lens.

• 한국인터넷방송통신학회논문지
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• 제14권3호
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• pp.147-153
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• 2014

본 논문에서는 안드로이드 플랫폼 기반의 스마트 감성조명 제어 시스템을 제안한다. 제안된 스마트 감성조명제어 시스템은 안드로이드 플랫폼, 감성조명 장치, 확장 디바이스와 지그비 모듈을 사용하였다. 안드로이드 플랫폼 기반의 스마트 감성조명 제어 시스템은 조도센서를 이용하여 자동제어와 수동제어 선택이 가능하며, 원하는 조명만을 선택하여 부분적인 제어도 가능하게 설계하였다. 제안된 스마트 감성조명 제어 시스템의 실험 결과 필요로 하는 부분의 조명기기 제어와 색온도 가변에 의한 제어가 가능하였고, 감성어휘에 의한 가변점등으로 효율적으로 기존 감성조명 제어 시스템보다 전력 소비를 감소시켰다. 그리고 상황에 적합한 색상과 밝기를 제어하여 사무실에서 행위를 함에 있어 집중력과 업무능력 향상에도 효과적인 제어가 가능하였다.

• 동력기계공학회지
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• 제12권6호
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• pp.50-55
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• 2008

In general, the swing motion of the crane is controlled and suppressed by activating the trolley motion. In many papers reported by us, we suggested a new type of anti-sway control system of the crane. In the proposed control system, a small auxiliary mass(moving-mass) is installed on the spreader and the swing motion is controlled by moving the auxiliary mass. The actuator reaction against the auxiliary mass applies inertial control forces to the container in order to reduce the swing motion in the desired manner. Futhermore the measuring systems based on image sensor have been proposed also. To obtain the robustness for our control system, $H_{\infty}$ based control techniques and other approach have been applied to suppress swing motion. As well known, the robust control technologies based on $H_{\infty}$ control need complicated and difficult process. In the result, the obtained closed-loop system becomes to high order system which may give us many difficulties to apply it to the real plants. Therefore, we introduce an easy approach which is based on LQ control theory. In this approach, we introduce the frequency dependent weighting matrices which give the system filters to shape frequency characteristics of the controlled system and guarantee the control performance.

• 복식
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• 제62권6호
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• pp.139-153
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• 2012

To prolong the rapid progress of IT, it is necessary to develop contents through IT convergence among the existing goods & service and process areas to create new added-values. In particular, the wedding dress industry has infinite potential in utilizing various contents like virtual fitting by connecting with newly compelling IT areas such as smart phones, Augmented Reality (AR), and application contents. In the meantime, a large scale of the wedding industry has gained global competitiveness due to consulting expertise and the influence of the Korean Wave, whereas most small-sized wedding dress shops in Korea fall short of developing wedding dress designs and receiving relevant information. Accordingly, the purpose of this study was to help brides who have difficulties in choosing a wedding dress by decreasing their time and effort by providing wedding dress designs and information, according their desired image, body type, and circumstances through the utilization of virtual fitting application contents. Not only that, this study aims to diversify and specialize in wedding information and to help users to set a guideline for wedding dresses that are most suitable for them. Moreover, this study has an academic meaning in proposing an interdisciplinary convergence research model through the study of wedding dress design development, AR, and application contents utilization.

• International Journal of Aeronautical and Space Sciences
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• 제14권3호
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• pp.282-295
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• 2013

In order to communicate with a ground station, the tracking profile design problem for a directional antenna system is considered. Because the motions of the gimbal angles in the antenna system affect the image quality, the main object is to minimize the motion of the gimbal angles during the satellite's imaging phase. For this goal, parameter optimization problems in the imaging and maneuver phases are formulated separately in the body-frame, and solved sequentially. Also, several mechanical constraints, such as the limitation of the gimbal angle and rate, are considered in the problems. The tracking profiles of the gimbal angles in the maneuver phases are designed with N-th order polynomials, to continuously connect the tracking profiles between two imaging phases. The results confirm that if the vector trace of the desired antenna-pointing vector is within the antenna's beam-width angle, motions of the gimbal angles are not required in the corresponding imaging phase. Also, through numerical examples, it is shown that motion of the gimbal angles in the imaging phase can be minimized by the proposed design process.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.139-144
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• 2005

Because of the photorefractive recording dynamics, each newly recorded hologram partially erases all previously stored image. Thus achieving the desired diffraction efficiency profile for the entire sequence after all images have been recorded requires exposure time schedule. The often cited classical exposure-schedule model predicts a rising-exponential build-up and an exponential decay in An with an exposure time. However because we cannot directly measure the An, it's difficult to establish the relation of both. In this paper, we deduce the relation of diffraction efficiency and exposure time from experiment data and suggest an algorithm to make time schedule profile in angle/fractal multiplexing of holographic data storage. After that, we present simulated result with equal hologram diffraction efficiency for a sequence of 250 holograms recorded by angle/fractal multiplexing.