• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.73-81
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• 2005

We propose an automatic modulation recognition scheme which extracts pre-defined key features from the received signal and then applies equal gain combining method to determine the used modulation. Moreover, we compare and analyze the performance of the proposed algorithm with that of decision-theoretic algorithm. Our scheme extracts five pre-defined key features from each data segment, a data unit for the key feature extraction, which are then averaged over all the segments to recognize the modulation according to the decision procedure. We check the performance of the proposed algorithm through computer simulations for analog modulations such as AM, FM, SSB and for digital modulations such as FSK2, FSK4, PSK2, and PSK4, by measuring recognition success rate varying SNR and data collection time. The result shows that the performance of the proposed scheme is comparable to that of the decision-theoretic algorithm with less complexity.

• Journal of Digital Convergence
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• v.16 no.11
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• pp.353-361
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• 2018

The purpose of this study was to explore the lived experiences of university students who were placed under academic probation. A qualitative research design was used to understand the experiences of students. The data were collected using individual in-depth interviews with 4 students who had experiences of low academic achievements at least once during 5 semesters. Low self esteem was the main issue in this study and inner struggles were identified within 4 themes: Outstanding students controlled by helpers; A costume play as a outstanding student; Realize that I am a under academic achiever; Realize who I am and what I have to do. This study identified that low academic achievement brings to low self esteem seriously, however, human being has strong resilience in the traumatic circumstances. Thus, it is absolutely necessary devoting efforts to develop suitable student supporting programs in the way of inner and outer network systems.

• The Journal of Advanced Prosthodontics
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• v.9 no.6
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• pp.463-469
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• 2017

PURPOSE. To evaluate the fit of a three-unit metal framework of fixed dental prostheses made by subtractive and additive manufacturing. MATERIALS AND METHODS. One master model of metal was fabricated. Twenty silicone impressions were made on the master die, working die of 10 poured with Type 4 stone, and working die of 10 made of scannable stone. Ten three-unit wax frameworks were fabricated by wax-up from Type IV working die. Stereolithography files of 10 three-unit frameworks were obtained using a model scanner and three-dimensional design software on a scannable working die. The three-unit wax framework was fabricated using subtractive manufacturing (SM) by applying the prepared stereolithography file, and the resin framework was fabricated by additive manufacturing (AM); both used metal alloy castings for metal frameworks. Marginal and internal gap were measured using silicone replica technique and digital microscope. Measurement data were analyzed by Kruskal-Wallis H test and Mann-Whitney U-test (${\alpha}=.05$). RESULTS. The lowest and highest gaps between premolar and molar margins were in the SM group and the AM group, respectively. There was a statistically significant difference in the marginal gap among the 3 groups (P<.001). In the marginal area where pontic was present, the largest gap was $149.39{\pm}42.30{\mu}m$ in the AM group, and the lowest gap was $24.40{\pm}11.92{\mu}m$ in the SM group. CONCLUSION. Three-unit metal frameworks made by subtractive manufacturing are clinically applicable. However, additive manufacturing requires more research to be applied clinically.

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.347-353
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• 2018

PURPOSE. The purpose of this study was to evaluate the marginal discrepancy of heat-pressed ceramic veneers manufactured using a CAD/CAM system. MATERIALS AND METHODS. The ceramic veneers for the abutment of a maxillary left central incisor were designed using a CAD/CAM software program. Ten veneers using a microstereolithography apparatus (AM group), ten veneers using a five-axis milling machine (SM group), and ten veneers using a traditional free-hand wax technique (TW group) were prepared according to the respective manufacturing method. The ceramic veneers were also fabricated using a heat-press technique, and a silicone replica was used to measure their marginal discrepancy. The marginal discrepancies were measured using a digital microscope (${\times}160$ magnification). The data were analyzed using a nonparametric Kruskal-Wallis H test. Finally, post-hoc comparisons were conducted using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The $mean{\pm}SD$ of the total marginal discrepancy was $99.68{\pm}28.01{\mu}m$ for the AM group, $76.60{\pm}28.76{\mu}m$ for the SM group, and $83.08{\pm}39.74{\mu}m$ for the TW group. There were significant differences in the total marginal discrepancies of the ceramic veneers (P<.05). CONCLUSION. The SM group showed a better fit than the AM and TW groups. However, all values were within the clinical tolerance. Therefore, CAD/CAM manufacturing methods can replace the traditional free-hand wax technique.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.197-203
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• 2009

The users need the communication that interaction is possible in digital communication environment. It is necessity to develop the Interactive Character that various emotional expression was possible while a user-centered emotional display tool was necessary. It is a fundamental research that is going to develop the Interactive Character that individualized emotional expression is possible. In other words, I have the purpose that is going to show the aromaticness of the technology development to express feelings. Therefore, I am going to analyze whether no matter how much technology to express feelings mainly on a face expression is incarnated through an example. And, I am going to show the development direction of the Interactive Character as an emotional display tool through this.

• Journal of the Korean Magnetics Society
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• v.15 no.4
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• pp.250-255
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• 2005

A 8 MA/m-class pulsed field magnetometer has been constructed by composing a pulsed field magnet, a pickup coil, analog integrators, a digital storage oscilloscope and a personal computer. For precision measurements, a 3-axis compensation principle has been applied for the fabrication of pickup coil, and the compensation level of the order of $10^{-6}$ and the sensitivity of $5{\cdot}10^{-7}\;Am^2$ for magnetic moment have been obtained. The high sensitivity of the magnetometer is good enough for measurements of magnetic properties of rare earth magnets in small size or thin films shorter than $3\;mm{\phi}$ in diameter.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.102-107
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• 2000

In this paper, it is presented a new technique to the design and real-time implementation of fuzzy control system based-on digital signal processors in order to improve the precision and robustness for system of industrial robot. Fuzzy control has emerged as one of the most active and fruitful areas for research in the applications of fuzzy set theory, especially in the real of industrial processes. In this thesis, a self-organizing fuzzy controller for the industrial robot manipulator with a actuator located at the base is studied. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variable of the controller, In tile synthesis of a FLC, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult, SOFC is proposed for a hierarchical control structure consisting of basic level and high level that modify control rules.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.2
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• pp.88-97
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• 2016

Aesthetics can be affected by the interest and the trend of the time. There are the limits of the equipment and materials required for the times, aesthetic case is also considered necessary to overcome them and will introduce the following case in accordance with the patients demands and circumstances. I hope the further development of CAD/CAM by taking over the things have done in the analogue by utilizing the latest technology that is thought to challenge the current limit itself is important. Digital has the advantages in various perspectives. Especially, I am very interested in as related to "digital communication." In particular, when utilizing the data using intra oral scanner can easily direct converse about prosthesis between the dentist and the dental technician through a software program Now, as the digital communication affects the integrity of the prosthesis directly, I had a expectation of a new era for the prosthetic and aesthetics. In this case report, I would like to introduce direct and real digital communication through the following 2 parts.

• Archives of design research
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• v.12 no.4
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• pp.201-209
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• 1999

Feb. 11. 1997, Korean Government announced FM Radio Broadcasting and TV Terrestrial TV Broadcasting will be changed to digital format in year 2001, and all Korean Broadcasting except AM Radio and Microwave will be changed to digital format before 2010. In spite of IMF economic crisis, the Digitizing is the one of the hot issue in TV Broadcasting area. The narrow view of the Digitizing the Broadcasting is a technical development from the analogue to digital, but the extended view of it means not only the technical development but the revolution in the concept of TV and service area, relationship between sender and receiver, structure of TV Industry. Thus Digitizing the Broadcasting shifts paradigm and eventually it cause a big change in the advertising creative. The digital TV could be a very encouraging technical development for the consumers convenience because of the multiple choice in the channels and interactive services which leads us to the multimedia service through the TV . On the other hand, multimedia and multi-channel, interactivity implicate a big uncertainty and risk, This research paper is about the technical aspects and social aspects of digital TV and its influence of the marketing and TV advertising creative.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.127-136
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• 2006

Shaded relief is used in the analysis of digital terrain model, but accurate shadow zone has not been affirmed on account of idea only shadow of terrain that would be in shadow are shaded. This study is to analyze each display difference of a digital terrain model by grasping the shadow characteristics of terrain and comparing shaded relief function used terrain display of GIS with a rendering technique. After terrain with road in subject area is selected and created to digital terrain model of TIN, shaded relief and rendering according to altitude and azimuth of the sun at 9:00 am and 3:00 pm is applied. As the results, only backward portions of the terrain that is in shadow from the sunlight are shaded in case of shaded relief. The rendering created the shadow, which is cast by terrain features. By these mutual comparison, this study represented data for understanding of shaded relief. And it is expected that the rendering method could be used to analyze sunshine influence.