• Journal of Periodontal and Implant Science
• /
• v.44 no.4
• /
• pp.184-193
• /
• 2014

Purpose: The aim of the present study was to evaluate the in vivo accuracy of flapless, computer-aided implant placement by comparing the three-dimensional (3D) position of planned and placed implants through an analysis of linear and angular deviations. Methods: Implant position was virtually planned using 3D planning software based on the functional and aesthetic requirements of the final restorations. Computer-aided design/computer-assisted manufacture technology was used to transfer the virtual plan to the surgical environment. The 3D position of the planned and placed implants, in terms of the linear deviations of the implant head and apex and the angular deviations of the implant axis, was compared by overlapping the pre- and postoperative computed tomography scans using dedicated software. Results: The comparison of 14 implants showed a mean linear deviation of the implant head of 0.56 mm (standard deviation [SD], 0.23), a mean linear deviation of the implant apex of 0.64 mm (SD, 0.29), and a mean angular deviation of the long axis of $2.42^{\circ}$ (SD, 1.02). Conclusions: In the present study, computer-aided flapless implant surgery seemed to provide several advantages to the clinicians as compared to the standard procedure; however, linear and angular deviations are to be expected. Therefore, accurate presurgical planning taking into account anatomical limitations and prosthetic demands is mandatory to ensure a predictable treatment, without incurring possible intra- and postoperative complications.

• Proceedings of the Korean System Dynamics Society
• /
• 2003.02a
• /
• pp.29-55
• /
• 2003

최근의 통신서비스 시장은 경쟁의 도입과 기술의 발전이라는 두 축에 힘입어 양질의 서비스를 보다 저렴한 요금으로 소비자들에게 제공하고자 노력하여 왔다. 그러나 이러한 통신서비스의 질적 향상 노력에도 불구하고 여전히 통신서비스의 품질은 소비자들의 기대수준에는 미치지 못하고 있다는 지적이 있다 더욱이 문제가 되는 것은 소비자가 인지하고 있는 통신 서비스 품질의 기대수준은 시간의 흐름에 따라 동태적으로 변화하는 것이어서 한 시점에서의 통신 서비스 품질 수준의 측정으로는 정책적으로 큰 의미를 설명하기 어려운 실정이다. 이와 관련하여 많은 선행 연구들이 다양한 측면에서 시행되어져 왔지만 이제까지의 많은 선행 연구들은 대부분이 통신서비스의 특성을 제대로 고려하지 않고, 고객만족의 향상과 불일치를 가져오고 있는 성능품질만을 측정한다거나, 시간의 흐름에 따라 변화해 가는 소비자가 서비스에 대해 인지하고 있는 중요도나 기대수준을 고려하지 않고 있으며, 각 구성요소간의 동태적 인과고리에 대한 고려 없이 연구가 이루어져 전반적인 통신 서비스의 고객만족을 전체적인 시각에서 평가한 연구는 극히 드물다. 따라서 본 연구는 통신서비스의 고객만족을 피드백 관점, 동태적 관점, 사실적 관점의 시스템 다이내믹스 방법론을 적용하여 전반적인 동태적 고객만족 모형을 구현하고 이를 정책적으로 활용할 수 있는가에 대한 접근을 시도하였다. 고객만족은 결코 한순간에 머물러 있는 것이 아니며 체감품질 및 기대수준의 영향을 받아 지속적으로 변화해간다 따라서 어떻게 기대수준을 관리하고 고객의 기대에 부응하는 체감품질을 관리하는 것이 지속적인 고객만족을 획득할 수 있는 가를 시뮬레이션 모형을 통해 가시적으로 시스템의 행태를 구현함으로써 그 이해의 폭을 넓히고자 시도하였다.으로써 웹에서의 혁신적이며 크로스 사이트, 크로스 장르적인 컨텐츠 플래닝의 가능성을 시사하는데 의의가 있다고 하겠다.y used to some of interactive storytelling through hyper text in CD-ROM and web sites. More complicated and different structured models were born through games that offered graphics, virtual spaces and interactivity. When drawn onto a structural graph, few attributes and similarities seem to occur. This paper will try to outline and discuss structural graphs of interactive storytelling methods and suggest some ways for better storytelling design.eal sales volume, but the case study could verified that this method is effective to the evaluation of marketability in case of completely new product got on the typical category and the product category could be set up the population clearly.의 무게와 부피는 24주간 다소 감소하는 경향을 보였으나 통계적인 유의차는 없었다. 냉동저장 감자의 무게와 부피 변화는 48주간 전혀 없었다. 상온 냉장저장 감자의 조직의 강도(hardness)는 24주

• Journal of Broadcast Engineering
• /
• v.25 no.2
• /
• pp.185-191
• /
• 2020

MPEG-I is actively working on standardization on the immersive video coding which provides up to 6 degree of freedom (6DoF) in terms of viewpoint. In a virtual space of 3DoF+, which is defined as an extension of 360 with motion parallax, looking at the scene from another viewpoint (another position in space) requires rendering an additional viewpoint using multiple videos included in the 3DoF+ video. In the MPEG-I Visual workgroup, efficient coding methods for 3DoF+ video are being studied, and they released Test Model for Immersive Video (TMIV) recently. This paper presents a patch packing method which packs the patches into atlases efficiently for improving coding efficiency of 3DoF+ video in TMIV. The proposed method improves the reconstructed view quality with reduced coding artifacts by introducing guardbands between patches in the atlas.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.27 no.1
• /
• pp.751-760
• /
• 2009

This research aims to develop the strategy and method to enhance the reliability of image matching results and improve the efficiency of the matching process by utilizing LIDAR data in the main image matching processes. In this work, we present the methods to utilize LIDAR data in the selection of matching entities, the search for the matched entities and the evaluation of the matching results. The proposed method has been applied to medium-resolution digital aerial images and LIDAR data acquired at the same time. The results have been analyzed in comparison with an existing method using a virtual horizontal surface rather than LIDAR DEM. This analysis indicates that the proposed method can show significantly more improved performance than the existing method. The results of this study can contribute to the improvement of the currently available commercial image matching software and the enhancement of the DEM derived from LIDAR data and matching results.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.8
• /
• pp.868-872
• /
• 2010

Many embedded Java systems are equipped with limited memory, which can constrain the code cache size provided for Java just-in-time compilation, affecting the Java performance. This paper proposes expanding the limited code cache when it is full, by saving the machine code for some methods in the code cache into the file system of the permanent storage and reloading it to the code cache when they are re-invoked later. This is applying the client ahead-of-time compilation during the execution time for the purpose of enlarging the code cache. Our experimental results indicate that the proposed execution method can improve the performance by as much as 1.6 times compared to the conventional method, when the code cache size is reduced by half.

• International Journal of Highway Engineering
• /
• v.18 no.5
• /
• pp.75-82
• /
• 2016

PURPOSES : This study was initiated to estimate the benefits from the campaign to prevent drowsy driving crashes on expressways. The study was conducted by the Korea Expressway Corporation using a contingent valuation method. METHODS : First, a questionnaire was designed for a preliminary survey. From the survey's results, the initial willingness to pay for the campaign was determined by averaging different amounts of payments chosen under virtual scenarios in the survey. The willingness to pay data was used to find a first bid price for the open-ended method used for the second survey. After that, a primary questionnaire was designed and conducted using a single dichotomous choice question (SDBCQ). Drivers at expressway resting areas were asked their willingness to pay for the campaign. Based on statistical analysis using data collected from the second survey, the mean willingness to pay was estimated using a probability utility function. Finally, the benefit from the campaign was calculated using the estimated willingness to pay and accident data on expressways. CONCLUSIONS : Based on the result from the contingent valuation method, the benefit from the campaign to prevent drowsy driving crashes was estimated to be 170.6 won per expressway trip. The benefit is to be paid as an additional toll. In addition, the traffic crash cost estimate is about 2,209,680,000 won less than the cost during the same period in 2014.

• Fashion & Textile Research Journal
• /
• v.20 no.2
• /
• pp.143-155
• /
• 2018

The purpose of this study is elucidate the status and role of fashion house museums including art museums that are affiliated to luxury fashion brands. This study is significant in that it offers profound understanding of the history of luxury brands and the direction of communication these luxury brands are taking through online and offline museums. For research methods in this study, literature review and case studies were combined. Based on the luxury type classification by Sicard, the scope of research was determined to include the French classical luxury brands to modern luxury brands and contemporary luxury brands. Examining the current status of fashion house museums, it was found that Cartier Foundation for Contemporary Art is an art museum operated by the luxury fashion brand, Cartier. Other fashion house museums in operation included $Herm{\grave{e}}s$ Museum, Foundation Louis Vuitton Museum, $Crist{\acute{o}}bal$ Balenciaga Museum, Yves Saint Laurent Museum, Gucci Museum, Christian Dior Museum, Prada Foundation Museum, Ferragamo Museum, Armani Silos, and so on. As for online museums, there was Valentino Garavani Virtual Museum. These luxury fashion brands' museums serves the following roles: provides references to the fashion industry professionals and researchers; differentiates the brand as means of experience marketing; promotes the brand and enhances brand communication through exhibitions of the founder and designers; archive the brand's design and builds the brand's history as a means of storytelling marketing.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.4
• /
• pp.1540-1551
• /
• 2015

The detection of position and speed in BLDC motors without using position sensors has meant many efforts for the last decades. The aim of this paper is to develop a sensorless technique for detecting the position and speed of BLDC motors, and to overcome the drawbacks of position sensor-based methods by improving the performance of traditional approaches oriented to motor phase voltage sensing. The position and speed information is obtained by computing the derivative of the terminal phase voltages regarding to a virtual neutral point. For starting-up the motor and implementing the algorithms of the detection technique, a FPGA board with a real-time processor is used. Also, a versatile hardware has been developed for driving BLDC motors through pulse width modulation (PWM) signals. Delta and wye winding motors have been considered for evaluating the performance of the designed hardware and software, and tests with and without load are performed. Experimental results for validating the detection technique were attained in the range 5-1500 rpm and 5-150 rpm under no-load and full-load conditions, respectively. Specifically, speed and position square errors lower than 3 rpm and between 10º-30º were obtained without load. In addition, the speed and position errors after full-load tests were around 1 rpm and between 10º-15º, respectively. These results provide the evidence that the developed technique allows to detect the position and speed of BLDC motors with low accuracy errors at starting-up and over a wide speed range, and reduce the influence of noise in position sensing, which suggest that it can be satisfactorily used as a reliable alternative to position sensors in precision applications.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.11
• /
• pp.1868-1878
• /
• 2016

This paper proposes a novel velocity estimator for long-term underwater navigation of autonomous underwater vehicles(AUVs). Provided that an external position fix is not given, a viable goal in designing a underwater navigation algorithm is to reduce the divergence rate of position error only using the sporadic velocity information obtained from Doppler velocity log(DVL). For such case, the performance of underwater navigation eventually depends on accuracy and reliability of external velocity information. This motivates us to devise a velocity estimator which can drastically enhance the navigation performance even when the DVL measurement is unavailable. Incorporating the Gertler-Hagen hydrodynamics model of an AUV with the measurement models of velocity and depth sensors, the velocity estimator design problem is resolved using the extended Kalman filter. Different from the existing methods in which an AUV simulator is regarded as a virtual sensor, our approach is less sensitive to the model uncertainty often encountered in practice. This is because our velocity filter estimates the simulator errors with sensor aids and furthermore compensates these errors based on the indirect feedforward manner. Through the simulations for typical AUV navigation scenarios, the effectiveness of the proposed scheme is demonstrated.

• Journal of the Korean Society of Physical Medicine
• /
• v.7 no.1
• /
• pp.87-94
• /
• 2012

Purpose : The purpose of this study was to examine the feasibility and efficiency of balance training program through an interactive video game regimen in people with chronic stroke. Methods : Thirty patients with chronic hemiparetic stroke were recruited. Participants were randomly assigned to either a control group (n=15) or an experimental group (n=15). The control group received the general physical therapy including of strengthening and balance exercise five times a week whereas the experimental group received a program of balance exercise with video game play based on virtual reality as well as the same typical physical therapy. The experimental group received 6 sessions for four weeks. Each session was given 5 minutes. An interactive computer game exercise regimen lasted 30 minutes without rest periods. Outcome measures for weight transfer to paretic side, non-paretic side and sit-squat-speed, sit-squat-length, sit-to-standspeed and sit-to-stand-area for the control group (n=15) and experimental group (n=15) before and after treatment were obtained by using the biorescure. Results: Outcomes demonstrated significant improvement in the experimental group compared with the control group in weight transfer to paretic side, non-paretic side and sit-squat-speed, sit-squat-length, sit-to-stand-speed. No significant training effect was showed in sit-to-stand-area between pretraining and post-training. Conclusion : An interactive computer game exercise based on task oriented approach for balance in chronic stroke were feasible. In other words, This regimen resulted in a greater improvement in dynamic balance for people with chronic stroke.