• 한국정보통신학회논문지
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• 제18권4호
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• pp.949-956
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• 2014

최근, 영상정보에 관련된 하드웨어 및 소프트웨어 등의 기술이 발달함에 따라 다양한 멀티미디어 서비스에 대한 수요가 증가 되고 있다. 그러나 영상 신호의 처리, 전송, 저장하는 과정에서 여러 외부 원인에 의해 영상의 열화가 발생되며, 영상 열화의 주된 원인은 잡음에 의한 것이다. 영상은 대부분 AWGN(additive white Gaussian noise)에 의해 훼손되며, 잡음 제거를 위한 연구가 활발히 진행되고 있다. 본 논문에서는 영상에 첨가되는 AWGN의 영향을 완화하기 위하여, 공간 영역에서의 저주파 및 고주파 특성이 우수한 잡음제거 알고리즘을 제안하였다. 그리고 시뮬레이션을 통해 기존의 방법들과 결과를 비교하였으며, 성능의 평가를 위하여 PSNR(peak signal to noise ratio)을 사용하였다.

• 한국조경학회지
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• 제25권4호
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• pp.30-38
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• 1998

Nowaday special attention is being paid to the conservation of all species or ecosystmes of sites for public projects. Many environmental conservation policies and projects in Japan emphasize the coexistence of man with nature and close contact with nature. The objectives of this study was to investigate policies and projects for the creation of areas for the close contact with nature in Japan, to characterize change of techniques for the space creation over times, and to classify those policies and projects implemented by many government agencies. This study was mainly carried out by literature survey of laws, policies and projects related to environmental conservation pertinent to national scale. Major findings of this study can be summarized as follows: First, two most significant turning points for the environmental conservation in Japan were the establishment of the Office of Environmental in 1971 and the enactment of many laws influenced by the awareness of global environmental problems since 1990. Second, polices and projects for the creation of areas for the close contact with nature started in 1960s by the Office of Forestry, and focused on planting and development of simple facilities in forests. And the conservation of natural environment, ecological restoration and the expansion of urban green spaces, and the creation of biotopes and other areas for the close contact with nature in urban areas were the major characteristics of environmental conservation in Japan during 1970s, 1980s, and 1990s, respectively.

• 환경영향평가
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• 제20권5호
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• pp.663-673
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• 2011

In the face of accelerating biodiversity loss and its significance in our coexistence with nature, biodiversity is becoming more crucial in sustainable development perspective. To estimate biodiversity in the future which provides valuable information for decision making system especially in the national level, a quantitative approach must be studied forehand as a baseline of the present status. In this study, we developed a large-scale map of Plant Species Richness (PSR, typical indicator of biodiversity) for Young-dong and Pyung-chang provinces. Due to the accessibility of appropriate data and advance of modelling techniques, reduction of variables without deteriorating the predictive power is considered by applying Genetic algorithm. In addition, a number of Correctly Classified Instances (CCI) with 10-fold cross validation which indicates the predictive power, was carried out for evaluation. This study, as a fundamental baseline, will be beneficial in future land work as well as ecosystem restoration business or other relevant decision making agenda.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권6호
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• pp.1914-1925
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• 2014

Inter-symbol interference (ISI) problem is inevitable when the guard interval (GI) is shorter than the delay spread (DS) for an orthogonal frequency division multiplexing (OFDM) system. Iterative techniques have been proposed to overcome such a problem. However, most of existing algorithms are not efficient for an OFDM system with a small GI working under the channel with a large DS. Especially in the case of the DS spans a longer time than the half of the OFDM symbol duration. On the other hand, conventional algorithms, which can reduce the effects of the severe ISI, often employ several impractical assumptions to support the conclusions. In this paper, we present a robust decision feedback equalizer (DFE) for the OFDM system to overcome the severe ISI problem. The proposed DFE removes the ISI in a same manner as the residual inter-symbol interference cancellation (RISIC) algorithm. However, the inter-carrier interference (ICI) is reduced via cyclicity removal instead of the cyclicity restoration used in the conventional algorithms. The link-level simulation (LLS) results indicate that our proposed DFE scheme can dramatically improve the BER performance when the DS spans longer than the half of ODFM symbol duration.

• 한국정보컨버전스학회:학술대회논문집
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• 한국정보컨버전스학회 2008년도 International conference on information convergence
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• pp.177-180
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• 2008

Surveillance Cameras such as CCTV easily found in places requiring security and the prevention of crimes such as public institutions, banks, etc. play an important role as they prevent all sorts of crimes, and provide a decisive clue fix settling a criminal case. But, in case that a far-off person is photographed, an original image should be enlarged to identify the person. And as for the technique of enlarging an image, it is important to enlarge and restore it close to its original image rather than to merely magnify it. For the enlargement and restoration of an image, techniques called interpolation are used; as for interpolation methods known hitherto, however, the higher the magnifying power is, the more deteriorated the quality of an image becomes to the extent that the image cannot be identified. Therefore, in this paper, we are going to propose a new technique whereby the face outline in an image is vectorized and restored by means of FDP(Facial Definition Parameter) standardized by the MPEG-4 SNHC FBA group, and an image is restored to have better quality than images restored with the existing interpolation.

• 대한치과의사협회지
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• 제56권7호
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• pp.366-374
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• 2018

Purpose : The purpose of this study was to compare the marginal fit of monolithic zirconia restorations fabricated form the conventional and the digital impression technique. Materials and methods : Ten patients were restored with monolithic zirconia restorations fabricated from the digital and the conventional impression technique. Before definitive insertion, silicone replicas were produced from all twenty crowns. The silicone replicas were cut in three sections; each section was evaluated at two points. The measurement was carried out by using a measuring microscope (Olympus BX 51) and I-Solution. Data from the silicone replica scores were analyzed by Shapiro-Wilk test for normal distribution and the t-test for equality of two population's mean. All tests were performed with ${\alpha}-level$ of 0.05. Results : The average marginal gaps of monolithic zirconia restorations were $133.81{\pm}36.46{\mu}m$ for the conventional impression technique, $90.07{\pm}9.47{\mu}m$ for the digital impression technique. No statistical differences were found between the two impression techniques Conclusion : Both prostheses presented clinically acceptable results with comparing the marginal fit.

• 대한치과의사협회지
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• 제52권8호
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• pp.456-463
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• 2014

Caries Management by Risk Assessment (CAMBRA), published by California Dental Association in 2003, is a customized caries care system that classifies individuals' caries risk into 4 risk groups based on objective evidences and provides chemical treatments targeted for each caries risk level. However, this system was not only developed but also optimized for situation in the United States, resulting into many limitations to be used in Korea, and thus Korean CAMBRA (K-CAMBRA) that considers the clinical situation in Korea needs to be developed. K-CAMBRA includes various techniques that are newly developed in order to overcome the limitations. First, Q-ray, a new optical technology, is utilized in order to avoid the subjectivity of visual inspection during assessment of disease indicators and risk factors. Moreover, Cariview? that reflects the paradigm shift in cariology as a new form of caries assessment kit is used. In addition, considering the situation in Korea, where it is impossible to use high concentration fluoride product, Oral pack with a customized tray is added to increase the contact time of chemical substance. CAMBRA is believed to be the key clinical tool that overcomes the limitations of the paradigm of the conventional restoration-based surgical model of dentistry. Furthermore, it can be expected that Korean dentists can act as oral physicians who are able to control and care individuals' caries risk rather than operative experts who only care about the outcome of caries.

• Clinics in Shoulder and Elbow
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• 제19권1호
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• pp.51-58
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• 2016

The arthroscopic rotator cuff repair is now considered a mainstream technique with highly satisfactory clinical results. However, concerns remain regarding healing failures for large and massive tears and high revision rate. In recent decades, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. The focus of biomechanical test in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. Recent studies have shown that a transosseous tunnel technique provides improved contact area and pressure between rotator cuff tendon and insertion footprint, and the technique of using double rows of suture anchors to recreate the native footprint attachment has been recently described. The transosseous equivalent suture bridge technique has the highest contact pressure and fixation force. In this review, the biomechanical tests about repair techniques of rotator cuff tear will be reviewed and discussed.

• 건축역사연구
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• 제28권4호
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• pp.27-36
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• 2019

The traditional earth wall structure consists of a Joongkit(a small reinforcing post inside a wall) and a Oe(a miscellaneous tree, rendered laths) based on the space between the columns and applying the soil. The members who act as the base layer before applying soil used joongkit, sakmok, and oemok, which are known to correspond to the current joongkit, gasisae, and lath strips. This study was designed to understand the following through an analysis of the ancient texts, such as uigwe. Through a study on the usage and specifications of joongkit recorded on the uigwe, I wanted to reveal that joongkit is a material that has different specifications, functions, and installation techniques from current joongkit. The purpose of this study was to present the differences and technical features of the components of use for two types of oeyeokki technique of traditional wall. In addition, the items to be considered at the actual cultural heritage repair site were reviewed in the restoration of the earth wall weaving technique.

• Archives of Plastic Surgery
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• 제46권4호
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• pp.381-385
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• 2019

Hypospadias is a congenital malformation of the male genitalia. The reconstructive objectives are to obtain voiding with laminar flow and satisfactory sexual function. Several urethroplasty techniques have been described, but for perineal or revisional cases no single technique has shown robust success. In this study, we describe the expanded use of intestinal flaps for urethral reconstruction and report a peculiar request from a patient to undergo peno-urethral separation after successful hypospadias repair with a free ileum flap. A 51-year-old male patient with perineal hypospadias underwent several urethral reconstructive procedures with poor outcomes. A free ileum flap was attempted as a substitute for the urethra. Following successful reconstruction, separation of the neo-urethra (ileum) from the penile body was performed to address the patient's sexual expectations. A free ileum flap proved to be a reliable urethral substitute in perineal hypospadias reconstruction, with a successful outcome. The peno-urethral separation with the creation of an "accessory penis," however peculiar, optimized the results in terms of both sexual and urinary function. Anatomical restoration of the urethra and patient-reported expectations are the key to successful hypospadias reconstructive procedures. Sexual function outcomes and the patient's perception of success should not be underestimated, even when urinary function has been restored.