• 한국통신학회논문지
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• 제32권10C호
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• pp.1025-1031
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• 2007

본 논문에서는 송수신 안테나가 각각 4개인 MIMO-OFDM 시스템을 위한 효율적인 FFT 프로세서 구조를 제안한다. MIMO-OFDM 시스템의 기본은 다중 데이터 패스의 전송이므로 기존의 SISO-OFDM 시스템의 FFT 프로세서를 MIMO-OFDM 시스템에 그대로 적용하면 하드웨어 복잡도가 데이터 패스의 수에 선형적으로 증가하게 된다. 따라서 MIMO-OFDM 시스템에 맞도록 저면적의 다채널 FFT 프로세서가 요구된다. 제안된 FFT 프로세서는 다채널 MDC구조를 갖기 때문에 MIMO-OFDM 시스템의 다중 데이터 패스를 효과적으로 처리할 수 있으며, mixed radix 기법을 통한 효율적인 radix 분해를 이용하여 비단순 승산의 수를 감소시켰다. 제안된 구조를 갖는 FFT 프로세서는 HDL을 사용하여 설계된 후 0.18um CMOS 셀 라이브러리를 이용하여 설계되었다. 논리합성 결과, 4채널 radix-4 Multipath Delay Commutator (R4MDC) FFT 프로세서와 비교시 약 25%의 하드웨어가 감소함을 확인하였다. FFT 프로세서는 전체 MIMO-OFDM 시스템에서 약 30% 정도를 차지하는 커다란 블록이기 때문에, 제안된 FFT프로세서는 MIMO-OFDM 시스템의 하드웨어 복잡도를 감소시키는데 큰 공헌을 할 수 있다.

• 대한방사선기술학회지:방사선기술과학
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• 제42권6호
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• pp.469-476
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• 2019

The purpose of this study examines the education, knowledge and behavior of radiation safety management among dental workers and compares the education, knowledge and behavior between dental hygienist group and other occupational groups. This study was conducted from November 2nd to November14th, 2019. The survey was conducted on dental workers(dental hygienists, nursing, assistants, coordinators, etc.) who worked in dental hospitals and clinics in Busan area. The tool of this study was modified and adapted to the clinical setting based on the questionnaire. Radiation safety education has 39 dental hygienists who had more education than non-dental hygienists (p=0.286). The most common types of radiation safety education were self-education which usually performed by dentistry, followed by conservative education and others. The average of radiation attitudes, knowledge and behaviors was higher in the dental hygienist group then in the non-dental hygienist group. On the item-specific behavior among employees, the question of 'the radiation should be shielded according to the menstrual cycle or pregnancy of the woman of childbearing' was significant (p<0.05). On the item-specific knowledge between occupations, the question of 'the intensity of X-rays decreases over distance' and 'the individual exposure can be measured by TLD badge or film badge' was significant (p<0.05). Taken together, these results indicate that the dental hygienist group is more concerned about radiation safety and that the dental hygienist group is receiving more radiation safety management training. However, if there is a low level of 'has experienced' in the presence or absence of safety management education, it is difficult to train radiation safety management in dentistry. Therefore, it is considered that dentists should be trained in radiation safety management periodically to pay attention to radiation safety accidents.

• Radiation Oncology Journal
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• 제8권1호
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• pp.79-84
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• 1990

1984년부터 1988년까지 인제대학교 의과대학 치료방사선과에서 전이성 암에의해 발생한 악성 폐쇄성 황달환자 13명을 대상으로 간문을 포함하는 국소방사선치료를 시행하였다. 총 3명의 환자중 추적가능한 7명은 표준 방사선 조사야에 2.6주에서 6주 동안에 걸쳐 $2600\~5480$cGy의 방사선 조사를 받았으며 이중 5명은 완전관해, 1명은 부분 관해를 보여주었다. 전체 13명의 환자에서의 평균 생존기간은 3개월 이었으며 7명의 추적가능한 환자에서는 10.5개월이었다. 완전 관해를 보인 환자 5명중 2명은 황달의 재발없이 1년 이상의 생존기간을 보여주었다. 따라서 간문의 전이성 암으로 인해 발생한 악성 폐쇄성 황달 환자에 있어서 간문을 포함하는 조사야의 국소적 방사선 치료는 황달 해소와 증상완화에 많은 도움을 줄 수 있는 것으로 생각된다.

• 한국물환경학회지
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• 제31권6호
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• pp.693-699
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• 2015

It has been known that torrential rainfall events have been occurring worldwide due to climate change. The accelerated soil erosion has caused negative impacts on water quality and ecosystem of receiving waterbodies. Since soil security issues have been arising in various areas of the world, intensive interests have been given to topsoil management in Korea. Thus in this study, Web GIS-based computing system of physical, chemical, and biological topsoil quality indices were developed. In this study, five soil quality maps at national scale and top soil erosion potential were prepared for evaluation of soil quality based on soil erosion potential. For this system, the open source Web GIS engine, OpenGeo, was used as core engine of the system. With this system, decision makers or related personnel in areas of soil erosion Best Management Practices (BMPs) would be able to find the most appropriate soil erosion BMPs based on soil erosion potential and soil quality at the area of interest. The Web GIS system would be efficiently used in decision making processes because of ease-of-use interface and scientific data used in this system. This Web GIS system would be efficiently used because this system could provide scientific knowledge to decision makers or stakeholders. Currently various BMP database are being built to be used as a decision support system in topsoil management and topsoil quality areas.

• 한국물환경학회지
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• 제28권6호
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• pp.896-901
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• 2012

축사지역은 가축분뇨처리장으로부터의 오염물질 배출농도가 높아 인근 하천의 수질 및 수생태계에 큰 영향을 끼친다. 또한 강우시에는 축사주위에 축적되어 있던 각종 비점오염물질들이 강우유출수와 함께 유출되어 처리장 방류수와 함께 인근 하천의 주요 오염원으로 작용한다. 그러나 점오염원으로 배출되는 처리장의 배출수와 비점오염원 형태로 배출되는 강우유출수의 오염물질 유출특성이 달라 관리에 어려움을 겪고 있다. 본 연구에서는 축사지역의 점및 비점오염원의 특성을 분석하여 향후 가축분뇨 관리대책 수립에 필요한 기본자료를 제공하고자 한다. 연구대상지역은 10ha의 돈사 지역이며 모니터링은 2008년 10월부터 2011년 11월까지 3년동안 수행되었다. 입자상 물질 및 인의 배출농도는 비점오염원에서 높게 나타났으며, 유기물질 및 질소의 배출농도는 점오염원에서 높게 나타났다. 또한 비점오염원이 섞인 유출수에서는 TN/TP 비에 비해 낮은 BOD 농도를 보였다. 축사지역의 가축분뇨관리는 비점오염원에서의 입자상 물질 관리와 유기물질에 비해 높게 배출되는 점오염원의 영양염류 관리가 필요한 것으로 나타났다.

• Archives of Plastic Surgery
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• 제39권1호
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• pp.51-54
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• 2012

With the gradual increase of cases using fillers, cases of patients treated by non-medical professionals or inexperienced physicians resulting in complications are also increasing. We herein report 2 patients who experienced acute complications after receiving filler injections and were successfully treated with adipose-derived stem cell (ADSCs) therapy. Case 1 was a 23-year-old female patient who received a filler (Restylane) injection in her forehead, glabella, and nose by a non-medical professional. The day after her injection, inflammation was observed with a $3{\times}3cm$ skin necrosis. Case 2 was a 30-year-old woman who received a filler injection of hyaluronic acid gel (Juvederm) on her nasal dorsum and tip at a private clinic. She developed erythema and swelling in the filler-injected area A solution containing ADSCs harvested from each patient's abdominal subcutaneous tissue was injected into the lesion at the subcutaneous and dermis levels. The wounds healed without additional treatment. With continuous follow-up, both patients experienced only fine linear scars 6 months postoperatively. By using adipose-derived stem cells, we successfully treated the acute complications of skin necrosis after the filler injection, resulting in much less scarring, and more satisfactory results were achieved not only in wound healing, but also in esthetics.

• 한국물환경학회지
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• 제26권1호
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• pp.104-110
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• 2010

Eutrophication is a well-known phenomenon in lentic habitats, however it is receiving increasing attention in shallow streams of Korea due to the increase of periphyton to a nuisance level. In this study temporal and spatial variation in periphyton standing crop and nutrient concentrations were surveyed in the upper reach of the Han River (the Inbuk Stream) that used to be a pristine rural stream until 1980s. Chlorophyll-a concentration per unit surface area of bottom substrate was examined monthly for one year period at nine sites along the Inbuk Stream together with environmental factors such as phosphorus, nitrogen, and water velocity. The standing crop of periphytic algae ranged from $4{\sim}242mgChl.a/m^2$ with a median of $55mgChl.a/m^2$, often exceeding the nuisance level criterion. Along the stream periphyton increased significantly from $39{\pm}48mgChl.a/m^2$ to $94{\pm}49mgChl.a/m^2$ after merging of a tributary in an intensive agricultural basin with high phosphorus concentrations. Seasonally periphyton biomass was highest in autumn (median $171{\pm}76mgChl.a/m^2$) from October through December when water flow velocity was low (median $0.4{\pm}0.3m/s$), while it was higher in flood season (median $1.2{\pm}0.4m/s$) and freezing season (median $0.2{\pm}0.3m/s$) was lower. The result shows that this rural stream often shows characteristics of eutrophication according to periphyton standing crop and it may be regulated by phosphorus and water velocity.

• 한국습지학회지
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• 제12권3호
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• pp.165-175
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• 2010

급속한 산업화, 도시화 및 경제성장으로 다양한 개발사업이 발생하였다. 다양한 개발사업으로 인하여 각종 오염물질이 발생하였으며, 발생된 오염물질은 자연적으로 형성된 물순환 시스템이 아닌 인위적으로 형성된 물순환 시스템으로 인하여 하천 및 호소로 직접 유입되어 수질이 악화되고 있는 실정이다. 강우시 다양한 토지이용에서 발생하는 비점오염원이 큰 원인으로 나타나고 있다. 본 연구는 강우시 발생하는 비점오염물질 처리를 위한 저류 및 침투기능을 포함하는 한국형 비점오염저감시설인 Eco-Bio Filter (EBF)를 개발하고자 한다. EBF 시설은 저류 및 침투기능을 포함하며, EBF Test-bed를 공주대학교 천안 캠퍼스 내에 설치하여 다양한 강우사상에 대하여 모니터링을 수행하였다. 현재 모니터링 결과를 활용하여 기술의 문제점을 분석하고 개선하는 과정이 진행되고 있으며, 본 연구에서는 개선된 EBF 기술을 제시하였다. 오염물질별 저감효율을 분석한 결과, 입자상 물질, 질소, 인, 중금속에 대하여 70% 이상의 높은 저감효율을 나타내었다. 이러한 연구결과는 향후 국내 강우특성에 맞으며 도시의 생태를 확장할 수 있는 새로운 비점오염기술을 개발하는데 기초자료로 활용될 것이며, 저영향개발(LID) 중 하나가 될 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.2894-2909
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• 2015

As the number of mobile devices such as smart phones and tablets explodes, the need for new services or applications is also rapidly increasing. Smart class application is one of the emerging applications, in which most of contents are distributed to all members of a class simultaneously. It is highly required to select relay nodes to cover shadow area of radio as well as extend coverage, but existing algorithms in a smart class environment suffer from high control packet overhead and delay for exchanging topology information among all pairs of nodes to select relay nodes. In addition, the relay selection procedure should be repeated in order to adapt to the dynamic topology changes caused by link status changes or device's movement. This paper proposes the learning based relay selection algorithm to overcome aforementioned problems. The key idea is that every node keeps track of its relay quality in a fully distributed manner, where RQI (Relay Quality Indicator) is newly defined to measure both the ability of receiving packets from content source and the ability of successfully relaying them to successors. The RQI of each node is updated whenever it receives or relays broadcast packet, and the node having the higher RQI is selected as a relay node in a distributed and run-time manner. Thus, the proposed algorithm not only removes the overhead for obtaining prior knowledge to select relay nodes, but also provides the adaptability to the dynamic topology changes. The network simulation and experimental results prove that the proposed algorithm provides efficient and reliable content distribution to all members in a smart class as well adaptability against network dynamics.

• International Journal of Aeronautical and Space Sciences
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• 제9권2호
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• pp.121-128
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• 2008

Modularized GPS software defined radio (SDR) has many advantages of applying and modifying algorithm. Hardware based GPS receiver uses many hardware parts (such as RF front, correlators, CPU and other peripherals) that process tracked signal and navigation data to calculate user position, while SDR uses software modules, which run on general purpose CPU platform or embedded DSP. SDR does not have to change hardware part and is not limited by hardware capability when new processing algorithm is applied. The weakness of SDR is that software correlation takes lots of processing time. However, in these days the evolution of processing power of MPU and DSP leads the competitiveness of SDR against the hardware GPS receiver. This paper shows a study of modulization of GPS software platform and it presents development of the GNSS software platform using MATLAB Simulink™. We focus on post processing SDR platform which is usually adapted in research area. The main functions of SDR are GPS signal acquisition, signal tracking, decoding navigation data and calculating stand alone user position from stored data that was down converted and sampled intermediate frequency (IF) data. Each module of SDR platform is categorized by function for applicability for applying for other frequency and GPS signal easily. The developed software platform is tested using stored data which is down-converted and sampled IF data file. The test results present that the software platform calculates user position properly.