• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1686-1690
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• 2005

Although metal ball can be used as parts of bearing or metal filter, that is used by single product with solder ball or shot ball. Also, according as demand of metal ball of various diameter increase, processing property 솜 extension of coverage are important. Especially an optimal design of cutting roller was investigated for determining appropriate dimensions of components of manufacturing system. In this study, the effects of the diameter and the round radius of cutting roller were calculated and analyzed. We applied data of rigid-plastic FEM Simulation in basis design of equipment to solve these issues, and confirmed processing factor about metal ball manufacturing process that use cutting process of metal wire in this research

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.62-69
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• 1996

Lateral arm flap has been used for the reconstruction of the various defects in hand, head and neck region. This flap is highly dependable as a free flap because of its thin flap thickness, constant vascular anatomy and possibility of osteocutaneous flap and fascial flap. Recently, many authors tried extended approach for vascular pedicle and distal flap extension for bigger defects. In this study, we review previous articles and 14 cases used lateral arm flaps for coverage of the varying defect on head and neck, upper and lower extremities succesfully. In conclusion, lateral arm flap has constant anatomical structure and can overcome the disadvantages such as short pedicle length and limited flap size, then the range of its application can be very widened.

• Journal of Korean Library and Information Science Society
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• v.13
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• pp.29-58
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• 1986

The purpose of this study is to examine library service for the blind and visually disabled persons. the coverage of this study is 1) The Concept and categorization of blind and visually disabled persons 2) History of library service for the blind and visually disabled persons. 3) Activities and current situation of library service for the blind and visually disabled persons. 4) Activities of library service for the blind and visually disabled persons in Korea. 5) problems of library service for the blind and visually disabled persons. The followings are some of major points revealed in problems of library service for the blind and visually disabled persons. 1. Attitudinal barriers which grow out of prejudice because of lack of public awareness of all the information services for the blind and visually disabled persons. 2. The development and distribution of reading aids and innovative technology improving access to information for the blind and visually disabled persons. 3. Extension of information service in public library for the blind and visually disabled persons. 4. Copyright problems. 5. Facilities or architectural problems for the blind and visually disabled persons.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.46-49
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• 2007

Multiple Antenna Technologies such as Multiple-Input Multiple-Output (MIMO) and Beamforming provide the increase of channel capacity and the reliability of wireless link. To obtain these advantages, WiBro, Mobile WiMAX and $4^{th}$ Generation System are employing multiple antenna technologies. There exist, however, many technical issues in considering the application of the technologies or the providing of services using them. In this paper, various technical topics are discussed and simple solutions are proposed. Beamforming has several technical issues which include coverage imbalance, difficulties in providing Multicast-Broadcast Service (MBS). In Addition, network planning is a critical point from a cell extension and initial network entry point of view. In case of MIMO, network deployment is discussed in that cellular data network such as WiBro has many repeaters. MIMO mode selection for maximizing the cell capacity is also covered.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.251-252
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• 2008

Throughput and quality-of-service (QoS) over multi-cell environments are two of the most challenging issues that must be addressed when developing next generation wireless network standards. Currently, multiple-input/multiple-output (MIMO), inter-cell coordination and multi-hop relay technologies are viable options for improving channel capacity or coverage extension. Nevertheless, severe QoS degradation occurs in the outer region of multi-cells due to significant interference from neighboring cells or relay stations, thereby limiting overall performance. Therefore, we propose a scheme which adapted to hybrid relaying.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.109-115
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• 2009

Recently, the relay communication is focused for the power saving and coverage extension of ad-hoc networks. For the high date rate transmission, it is proposed to adapt OFDMA relays. In this paper, we assume the 2 hop cooperative OFDMA relays between the source and the destination. The performance of 3 different relaying methods are derived and compared. We noticed that the selective OFDMA relaying method has the best performance followed by opportunistic OFDMA relaying and repetition-based OFDMA relaying method under the same threshold mutual information rate.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.641-644
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• 2005

Cutaneous squamous cell carcinoma has a high incidence. However, regional metastasis occurs infrequently because skin cancer is usually recognized and treated early. We report the case of squamous cell carcinoma around the earlobe in a 74-year-old male patient. The cutaneous squamous cell carcinoma invaded ipsilateral parotid gland directly without lymphatic spreading. Wide excision was made with 1.5 cm margin and immediate reconstruction was performed with radial forearm fasciocutaneous free flap. During operation facial nerve was preserved. No recurrence was noted for 5 years and the patient was satisfied with good aesthetic result. Cutaneous squamous cell carcinoma spreads to the parotid gland usually through lymph nodes and there are few reports of invasive organ damage by direct invasion. We experienced a case of direct invasion to parotid gland without lymph node involvement of cutaneous squamous cell carcinoma and treated the cancer adequately with wide excision and free flap coverage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.2889-2909
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• 2017

Wireless sensor networks (WSNs) have attracted lots of attention in recent years due to their potential for various applications. In this paper, we seek how to efficiently deploy relay nodes into traditional static WSNs with constrained locations, aiming to satisfy specific requirements of the industry, such as average energy consumption and average network reliability. This constrained relay node deployment problem (CRNDP) is known as NP-hard optimization problem in the literature. We consider addressing this multi-objective (MO) optimization problem with an improved Artificial Bee Colony (ABC) algorithm with a linear local search (MOABCLLS), which is an extension of an improved ABC and applies two strategies of MO optimization. In order to verify the effectiveness of the MOABCLLS, two versions of MO ABC, two additional standard genetic algorithms, NSGA-II and SPEA2, and two different MO trajectory algorithms are included for comparison. We employ these metaheuristics on a test data set obtained from the literature. For an in-depth analysis of the behavior of the MOABCLLS compared to traditional methodologies, a statistical procedure is utilized to analyze the results. After studying the results, it is concluded that constrained relay node deployment using the MOABCLLS outperforms the performance of the other algorithms, based on two MO quality metrics: hypervolume and coverage of two sets.

• Journal of Environmental Science International
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• v.14 no.11
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• pp.1005-1014
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• 2005

The purpose of this research was to present multi-criteria which were related to the heat island and find methods which decreased heat island affection on the ecological landscape planning. The results of this study were as follows. According to the analysis of surface temperatures, the first grade was the outside-city like a mountain and its temperature was less than $13.0^{\circ}C$. The fifth grade was the downtown, industrial area and its temperature was more than $26.9^{\circ}C$. Therefore, the result was seen the serious heat-island effect. The results of field survey, the closer to the first grade, the higher the value of green coverage. The closer to the fifth grade, the higher the value of impermeability surface, paving materials and colors. According to the correlation analysis, the temperature had high correlation with impermeability surface, paving materials and colors. According to the simple regression analysis, permeability surface, green coverage, topography, impermeability surface, paving materials f: colors, human impact related with surface temperatures. To plan for the decrease of Heat-Island Effect needed the extension of green space, decrease of impermeability surface. This research suggested data for urban green plan and decrease of heat island effect, but there was a limit to get the objective method for grade classification because of lacking in the basic data, the research of multi-criteria will be accomplished continuously.

• Korean Journal of Remote Sensing
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• v.27 no.6
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• pp.637-651
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• 2011

This study presents a rule-based urban image classification method for time series analysis of changes in the vicinity of Asan-si and Cheonan-si in Chungcheongnam-do, using Landsat satellite images (1991-2006). The area has been highly developed through the relocation of industrial facilities, land development, construction of a high-speed railroad, and an extension of the subway. To determine the yearly changing pattern of the urban area, eleven classes were made depending on the trend of development. An algorithm was generalized for the rules to be applied as an unsupervised classification, without the need of training area. The analysis results show that the urban zone of the research area has increased by about 1.53 times, and each correlation graph confirmed the distribution of the Built Up Index (BUI) values for each class. To evaluate the rule-based classification, coverage and accuracy were assessed. When Optimal allowable factor=0.36, the coverage of the rule was 98.4%, and for the test using ground data from 1991 to 2006, overall accuracy was 99.49%. It was confirmed that the method suggested to determine the maximum allowable factor correlates to the accuracy test results using ground data. Among the multiple images, available data was used as best as possible and classification accuracy could be improved since optimal classification to suit objectives was possible. The rule-based urban image classification method is expected to be applied to time series image analyses such as thematic mapping for urban development, urban development, and monitoring of environmental changes.