• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.129-132
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• 2004

본 논문에서는 비전 기반 구륜이동로봇이 복도를 주행하기 위해 필요한 벽면으로부터의 거리와 방향각을 신경망을 이용하여 추정하는 알고리즘에 대해 기술하였다. 복도에 설치된 조명을 표식으로 사용하였고, 구륜이동로봇의 위치와 각도에 따라 조명들의 배열선과 정의된 소멸점의 위치는 다르게 된다. 따라서 조명의 배열선과 소멸점의 위치에 관한 두개의 평면을 구성하였다. 조명의 배열선과 소멸점의 위치는 간단한 영상처리 알고리즘을 통하여 획득하였다. 기지의 위치와 각도에서의 조명의 배열선과 소멸점의 위치에 대한 데이터를 획득하였다. 획득된 데이터를 이용하여 신경망을 구성하고 학습시켰다. 학습을 통해 수정된 신경망을 이용하여 실제 주행에 적용하였다.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.188-190
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• 2008

본 논문에서는 초음파 센서를 이용하여 이동하는 표적의 위치를 실시간으로 추적하는 위치추적 시스템을 개발하였다. 위치 추적 시스템은 4 개의 초음파 센서를 이용해서 각 센서에서 탐지되는 표적까지의 거리 정보를 이용하여 이동하는 표적의 위치좌표(x,y)를 구하였다. 특히 초음파 센서가 가지고 있는 빔폭 특성을 고려하여 4 개 센서 중 2개 센서에만 표적이 탐지될 경우 표적의 위치를 최적화하는 방안을 제시하였으며 개발된 알고리즘을 하드웨어에 장착하어 감시시스템이 실시간 양호하게 구동하는것을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1677-1678
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• 2015

본 논문에서는 3D Skeleton Model로부터 획득된 관절 정보를 이용하여 제스처를 인식할 수 있는 방법을 제안한다. 사람의 신체 크기나 비율은 다르더라도 구조는 같다는 사실을 바탕으로, 관절과 관절이 이루는 각도를 이용해 제스처를 인식한다. 몇 가지 제스처를 선정한 뒤, 실험을 통해 제안한 방법의 인식률을 측정해 보았다. 또한 동적 제스처 인식을 위한 기초를 다지기 위해 이동 방향과 이동 거리, 이동 위치를 측정하는 실험을 해 보았다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.202-204
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• 2018

본 논문에서는 부분 홀로그램의 중심점과 카메라의 이동에 따라 생성되는 시점 영상들의 상관성을 분석하였다. 같은 기준에서의 실험을 위하여, 물체의 실제 크기 및 시점간 거리 등의 파라미터를 조정하였으며, 카메라의 수평이동과 부분 홀로그램의 중심점이 좌, 우로 이동된 결과를 생성하는 실험을 진행하였다. 결과를 기반으로, 서로 다른 광학계와 생성방법을 통하여 생성된 임의의 시점 영상들의 상관성을 분석한다.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.4
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• pp.1-7
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• 2012

This paper proposes a new indoor location recognition system using a ZigBee network and a global positioning system(GPS). The proposed location recognition system applies GPS values that are mainly used for outdoor location recognition, to indoor location recognition; hence the techniques conventionally separated for the indoor and outdoor location recognition are integrated into one location recognition technique. The proposed system recognizes a location using the distance between nodes. Although the distance between nodes can be calculated by measuring the strength of the received ZigBee signals, generally the measured distance is not accurate and has high error rates since the strength of the ZigBee signals is different depending on the distance. In order to reduce the error rate, we have subdivided the output power of the received ZigBee signals into five levels. When a moving node generates a signal, each fixed node transmits the received signal strength and its own GPS information to other nodes, so the moving node can find its own accurate location in terms of the received signals.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.241-245
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• 2010

Purpose: In this work we suggested a grating chart of vision test which could be used to measure the sense of distance and motion of object. Methods: A couple of gratings with periodic structure were fabricated. Through a lens the grating images showing geometrical shapes were projected on a vision test chart in order to form a new grating chart of vision test. In rotating and translating the gratings the examinee perceived the variation of position of gratings by the variation of the sense of distance and motion. Results: The results of the sense of distance and motion measured in rotating and translating the gratings showed the average errors of ~2.98% and ~1.73% at $\theta=15^{\circ}$ respectively compared to calculated values. Conclusions: The grating chart of vision test suggested in this work can be used as a new test chart that lets an examinee perceive a sense of distance and motion of object.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.35-43
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• 2013

Exercise such as walking is helpful to manage one's own weight and to counter life habit diseases such as obesity. Calorie consumption is usually calculated based on the distance walked. One way to measure the distance is by using steps and stride length. Most pedometers, including some applications in smart devices, are inaccurate, because they use a common value as the average stride length, even though each person has a different stride length. Moreover, the stride length differs depending on the walking pace, which will further increase the error. To address this, in this paper, I classify paces into three categories. Following that, I introduce a customized measurement of stride length, which is calculated based on the stride length corresponding to each pace category after obtaining x, y, z values from a 3-axis accelerometer in the smart device. In addition to this, I developed an application running on the smart device designed for the proposed measurement of stride. I have conducted three experiments for the assessment of the proposed measurement. In conclusion, I confirmed the effectiveness of this system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1271-1280
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• 2012

In the recent parking assistant systems, finding out the distance to the object behind a car is often performed by the range sensors such as ultrasonic sensors, radars. However, the installation of additional sensors on the used vehicle could be difficult and require extra cost. On the other hand, the motion stereo technique that extracts distance information using only an image sensor was also proposed. However, In the stereo rectification step, the motion stereo requires good features and exacts matching result. In this paper, we propose a fast algorithm that extracts the accurate distance information for the parallel parking situation using the consecutive images that is acquired by a rear-view camera. The proposed algorithm uses the quadrangle transform of the image, the horizontal line integral projection, and the blocking-based correlation measurement. In the experiment with the magna parallel test sequence, the result shows that the line-accurate distance measurement with the image sequence from the rear-view camera is possible.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.487-498
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• 1998

This study was conducted to investigate changes of airway size, tongue and hyoid position following orthognathic surgery in mandibular prognathism, and how they are adapted to new environment in time dependent manner. 37 patients, who had recieved orthognathic surgery, were selected for this study. lateral cephalogram of each patient was taken at preoperation, immediate postoperation, and over 6 month after operation, and were traced and analyzed The findings of this study were as follows : 1. The size of airway was not changed at PNS and Epiglottis level after operation, but it was changed slightly at 2nd cervical vertebra level. 2. The hyoid was moved inferoposteriorly at immediate postoperation, and then it shifted toward preoperative position, but it remained slightly inferoposterior position. The distance from hyoid to genial tubercle decreased continuously. 3. The position of tongue was moved inferoposteriorly at immediate postoperatioa and then it shifted toward preoperation position, but the root of the tongue remained inferoposteriorly. 4. The distance between tongue and hyoid was increased at immediate postoperation and slightly decreased during follow-up period. 5. The change of the mandibular position was not significantly correlated with changes of airway size, hyoid position, tongue morphology and tongue position.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.4
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• pp.503-508
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• 2010

Recently, the advance of mobile devices has made various services possible beyond simple communication. One of services is the predicting the future path of users and providing the most suitable location based service based on the prediction results. Almost of these prediction methods are based on previous path data. Thus, calculating similarities between current location information and the previous trajectories for path prediction is an important operation. The collected trajectory data have a huge amount of location information generally. These information needs the high computational cost for calculating similarities. For reducing computational cost, the meaningful location based trajectory model approaches are proposed. However, most of the previous researches are considering only the physical information such as stay time and the distance for extracting the meaningful locations. Thus, they will probably ignore the characteristics of users for meaningful location extraction. In this paper, we suggest a meaningful location extracting and trajectory simplification approach considering the stay time, distance, and additionally interaction information of user. The method collects the location information using GPS device and interaction information between the user and the others. Using these data, the proposed method defines the proximity of the people who are related with the user. The system extracts the meaningful locations based on the calculated proximities, stay time and distance. Using the selected meaningful locations the trajectories are simplified. For verifying the usability of the proposed method, we collect the behavioral data of smart phone users. Using these data, we measure the suitability of meaningful location extraction method, and the accuracy of prediction approach based on simplified trajectories. Following these result, we confirmed the usability of proposed method.