임펄스 UWB 네트워크에서의 일정진폭 다중접속 채널코딩

김동석(Tongsok Kim),김용철(Yong Cheol Kim) 대한전자공학회 2008 電子工學會論文誌-SC (System and control) Vol.45 No.6

이 논문은 임펄스 UWB 시스템을 위한 새로운 일정진폭 프리코딩을 제안한다. IEEE 802.15.4a 표준에 따르면 임펄스 UWB는 실내측위와 센서 데이터 전달에 사용될 수 있다. 대부분의 USN(ubiquitous sensor network)은 다중접속을 필요로 한다. 그러나 UWB 시스템은 다중접속으로 야기되는 중첩신호를 검출하는데 있어 제약성이 있다. 이를 극복하기 위하여 Wada 및 Kim의 CAMC(constant amplitude multi-code) 개념을 응용하였다. 제안하는 시스템은 체계적 일정진폭 프리코딩과 LDPC 디코딩으로 구성된다. 또한 컴퓨터 시뮬레이션을 통하여 BER 성능이 우수함을 확인하였다. In this article a novel constant amplitude precoding for impulse UWB system is proposed. According to IEEE 802.15.4a, impulse UWB can be used in indoor localization and sensor data transmission. Most USN(ubiquitous sensor networks) needs multiple access. However impulse UWB system has a limited capability to detect superpositioned signal induced by multiple access. To overcome this problem we have adopted the concept of CAMC(Constant Amplitude Multi-Code) deviced by Wada and Kim. The proposed system consists of systematic constant amplitude precoding and LDPC decoding. And this system shows a good BER performance in computer simulation.

유방암의 Imprint 표본에서 p53 단백 발현

김동석,이은희,김기권,김미진,이수정,Kim, Dong-Sug,Lee, Eun-Hi,Kim, Ki-Kwon,Kim, Mi-Jin,Lee, Soo-Jung 대한세포병리학회 1995 대한세포병리학회지 Vol.6 No.1

This study was carried out to determine the usefulness of imprint cytology for detecting p53 protein in breast carcinoma. NCL-DO7 (Novocastra, U.K.) was used to detect p53 protein immunocytochemically. A total of 33 cases was studied, Immunostaining of imprint cytology with NCL-DO7 was positive in 64% (21/33) and showed relatively high coincident rate (80%) with immunostaining of formalin-fixed, paraffin-embedded specimen p53 protein was related to negative estrogen receptor status, but not to the nuclear grade, lymph node metastasis, or tumor size. The fact that p53 protein expression was not related to nuclear grade might be due to predominance of nuclear grade 3. It was easier to determine the nuclear grade is one of the most important prognostic factors, in imprint cytology than in tissue specimen. p53 protein tended to be stained more strongly in imprint cytology than in tissue. It is concluded that the application of imprint cytology in p53 protein detection can be performed easily, and that it may contribute to the evaluation of prognostic factors in breast carcinoma.

모야모야병에서 염기성 섬모 세포 성장 인자의 역할

김동석,최중언,김세혁,양국희,김현숙,Kim, Dong-Seok,Choi, Joong-Uhn,Kim, Se-Hyuk,Yang, Kook-Hee,Kim, Hyeun-Sook 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.1

Objectives and Importance : The present study investigated the levels of basic fibroblast growth factor(bFGF) in the CSF of patients with moyamoya disease and its clinical significance. Methods : The levels of bFGF in CSF, taken from 26 hemispheres of 14 moyamoya patients and 20 patients without vascular anomaly(control group), were measured by an enzyme-linked immunosorbent assay. We analyzed the correlation between the level of bFGF and the clinical factors such as age, onset pattern, development of neovascularization, and cerebral circulation. Results : The CSF of moyamoya patients contained a high concentration of bFGF to a significant extent. The bFGF level was apparently elevated in the patients in whom neovascularization from indirect revascularization, such as modified encephalo-duro-arterio-synangiosis(EDAS) was well developed. A linear correlation between the values of bFGF and clinical progression was noted. Conclusions : The elevation of bFGF in moyamoya disease seems to be specific. Clinically, the bFGF level may be considered a useful indicator to predict the efficacy of indirect revascularization.

태양광/$TiO_2$ 반응기용 반사판 최적화에 관한 연구

김동석,박영식,Kim, Dong-Seog,Park, Young-Seek 한국환경보건학회 2006 한국환경보건학회지 Vol.32 No.4

The photocatalytic reactor using immobilized $TiO_2$ on silicone sealant was studied bench scale using solar light as the source of radiation. The influences of parameters such as shape, polishing extent and size of reflector, distance between reactor and reflector, an angle of inclination between reactor system and ground, were studies using Rhodamine B (RhB) as a model compound. respectively. The decolorization of round type among the reflector shapes was higher than that of the polygon and W type. The polishing extent of the reflector did not show the decolorization largely. The optimum size of reflector and distance between reactor and reflector were 38 cm and 6 cm, respectively.

3D OSEM 재구성 법에서 반복연산(Iteration) 횟수와 부분집합(Subset) 개수 변경에 따른 영상의 질 평가

김동석,김성환,심동오,유희재,Kim, Dong-Seok,Kim, Seong-Hwan,Shim, Dong-Oh,Yoo, Hee-Jae 대한핵의학기술학회 2011 핵의학 기술 Vol.15 No.1

Purpose: Presently in the nuclear medicine field, the high-speed image reconstruction algorithm like the OSEM algorithm is widely used as the alternative of the filtered back projection method due to the rapid development and application of the digital computer. There is no to relate and if it applies the optimal parameter be clearly determined. In this research, the quality change of the Jaszczak phantom experiment and brain SPECT patient data according to the iteration times and subset number change try to be been put through and analyzed in 3D OSEM reconstruction method of applying 3D beam modeling. Materials and Methods: Patient data from August, 2010 studied and analyzed against 5 patients implementing the brain SPECT until september, 2010 in the nuclear medicine department of ASAN medical center. The phantom image used the mixed Jaszczak phantom equally and obtained the water and 99mTc (500 MBq) in the dual head gamma camera Symbia T2 of Siemens. When reconstructing each image altogether with patient data and phantom data, we changed iteration number as 1, 4, 8, 12, 24 and 30 times and subset number as 2, 4, 8, 16 and 32 times. We reconstructed in reconstructed each image, the variation coefficient for guessing about noise of images and image contrast, FWHM were produced and compared. Results: In patients and phantom experiment data, a contrast and spatial resolution of an image showed the tendency to increase linearly altogether according to the increment of the iteration times and subset number but the variation coefficient did not show the tendency to be improved according to the increase of two parameters. In the comparison according to the scan time, the image contrast and FWHM showed altogether the result of being linearly improved according to the iteration times and subset number increase in projection per 10, 20 and 30 second image but the variation coefficient did not show the tendency to be improved. Conclusion: The linear relationship of the image contrast improved in 3D OSEM reconstruction method image of applying 3D beam modeling through this experiment like the existing 1D and 2D OSEM reconfiguration method according to the iteration times and subset number increase could be confirmed. However, this is simple phantom experiment and the result of obtaining by the some patients limited range and the various variables can be existed. So for generalizing this based on this results of this experiment, there is the excessiveness and the evaluation about 3D OSEM reconfiguration method should be additionally made through experiments after this. 현재 핵의학 분야에서는 디지털 컴퓨터의 급속한 발전 및 응용으로 인해 FBP 법의 대용으로 OSEM 알고리즘과 같은 고속 영상 재구성 알고리즘이 널리 이용되고 있다. 그 동안 여러 연구에서 파라미터 변경에 따른 OSEM 재구성 영상 질 변화에 대한 평가가 이루어져 왔으나, 어떠한 파라미터를 적용할 지에 관해서는 명확하게 정해진 것은 없다. 본 연구에서는 3D beam modeling을 적용한 3D OSEM 재구성 법에서 iteration 횟수와 subset 개수 변경에 따른 영상의 질 변화를 팬텀 실험과 환자 데이터을 통해 확인하고자 한다. 환자 데이터는 2010년 8월부터 9월까지 본원 핵의학과에서 Brain SPECT를 시행한 환자 5명을 대상으로 연구 분석하였다. 영상은 물과 $^{99m}Tc$ (500 MBq)을 균등하게 혼합한 Jaszczak 팬텀을 이용하여 Siemens사의 이중 헤드 감마 카메라 Symbia T2에서 획득하였다. 환자 데이터는 영상 재구성 시 환자 데이터와 팬텀 데이터 모두 iteration 횟수는 1, 4, 8, 12, 24, 48회, subset 개수는 2, 4, 8, 16, 32개로 변화를 주며 각각의 영상을 재구성하였다. 재구성된 각각의 영상에서 대조도와 영상의 잡음 정도를 가늠하기 위한 변이계수, FWHM을 산출하여 비교하였다. 팬텀 데이터와 환자 데이터에서 영상의 대조도와 공간해상력은 iteration 횟수와 subset 개수의 증가에 따라 모두 선형적으로 증가하는 경향을 나타냈으나 변이계수는 두 파라미터의 증가에 따라 향상되는 경향을 보이지 않았다. Projection 시간에 따른 비교에서도 Projection 당 10초, 20초, 30초 영상에서 모두 영상 대조도와 FWHM은 iteration 횟수와 subset 개수 증가에 따라 선형적으로 향상되는 결과를 나타냈으나 변이계수는 향상되는 경향을 보이지 않았다. 본 실험을 통해 3D beam modeling을 적용한 3D OSEM 재구성 법 영상에서도 기존의 1D와 2D OSEM 재구성 법과 같이 iteration 횟수와 부분집합 개수 증가에 따라 향상하는 영상 대조도의 선형적 관계를 확인할 수 있었다. 하지만 이는 단순한 팬텀 실험과 일부 환자 데이터 만으로 얻은 결과이고, 실제 임상에서는 보다 구조적으로 복잡한 대상과 다양한 변수들이 존재 가능하기 때문에 본 실험의 데이터만을 바탕으로 이를 일반화하기에는 무리가 있으며 차후 실험들을 통해 3D OSEM 재구성 법에 대한 평가가 추가로 이루어져야 할 것이다.

대구지역 지중온도의 변화예측

김동석,홍수진,박준표,Kim, Dong-Seok,Hong, Soo-Jin,Park, Jun-Pyo 한국데이터정보과학회 2009 한국데이터정보과학회지 Vol.20 No.4

기온과 더불어 지중온도는 기후 변동 및 농업 환경 예측의 중요한 기준이 되고 있다. 이 논문 에서는 대구지역의 1932년부터 1990년도까지의 토심 0.5m 지중온도의 연평균 변화와 1961년부터 2008년까지의 기온 자료를 이용하여 연평균 기온변화를 살펴보고, 지중온도와 기온의 관계 모델을 도출하였다. 이 모델을 통하여 현재 측정되지 않는 대구의 지중온도를 기온을 이용하여 복원하였으며 그 결과 지중온도는 매년 약 $0.028^{\circ}C$의 증가를 보이고 있다는 사실을 확인할 수 있었다. 복원을 통한 지중온도의 예측은 대구 지역 기후 변화 예측의 중요한 기준이 되며, 농업 환경의 변화에 대한 FTA 협약, 지구온난화 등에서 발생가능한 상황의 대비책을 마련할 수 있는 정보가 되겠다. Soil temperature is an important tool in predicting a change of climate and agricultural environment together with the change of atmospheric temperature. In this paper, we examine changing patterns of soil temperature measured in 0.5m under ground from 1932 to 1990 and atmospheric temperature from 1961 to 2008, and derive a relationship between atmospheric temperature and soil temperature. Using this model, we predict unmeasured soil temperature in Daegu area and soil temperature is found to be increasing about $0.028^{\circ}C$per a year. Prediction of soil temperature is an important indicator for climate change in Daegu and will be useful information to help us take precautions for global warming, etc.

미분무수 소화설비의 성능평가방법

김동석,Kim, Dong-Seok 한국화재소방학회 2009 한국화재소방학회지 Vol.5 No.1

유전체 장벽 방전 플라즈마 방전수의 특성과 미생물 소독에 관한 연구

김동석,박영식,Kim, Dong-Seog,Park, Young-Seek 한국환경보건학회 2012 한국환경보건학회지 Vol.38 No.2

Objectives: This experiment was carried out to elucidate the effect of discharged water on the disinfection of $Phytophthora$ $capsici$ and evaluate the water characteristics. Methods: The dielectric barrier discharges (DBD) plasma reactor system used in this study consisted of a plasma component [discharge, ground electrode and quartz dielectric tube], high voltage source, and air supply. The effects of water characteristics such as pH, ORP and conductivity and the disinfection effect of discharged water were investigated. Results: Experimental results showed that in the process of discharge, the pH decreased, whereas ORP and electric conductivity increased. When the discharge time was 30 min, $Phytophthora$ $capsici$ of 2.94 log was disinfected within 300 seconds. Disinfection performance of stored discharged water was maintained for three days; however the disinfection effect vanished after five days. When $Phytophthora$ $capsici$ was injected into the discharged water, the disinfection effect decreased after two days. Conclusions: It is considered that the main disinfection parameters of the discharged water were chemically active species such as $H_2O_2$ and $O_3$ and high ORP.

멀티 플라즈마 반응기를 이용한 E. coli 소독

김동석,박영식,Kim, Dong-Seog,Park, Young-Seek 한국환경보건학회 2013 한국환경보건학회지 Vol.39 No.2

Objectives: For the practical application of the dielectric barrier discharge plasma reactor, a plasma reactor able to manage large volumes of water is needed. This study investigated the possibility of the practical application of a multi-plasma reactor which is a scaled-up version of a single plasma reactor. Methods: The multi-plasma reactor consists of several high-voltage transformers and plasma modules (discharge, ground electrodes and quartz dielectric tubes). The effects of water characteristics such as voltage (30-120 V), air flow rate (1-5 l/min), number of high-voltage transformers and plasma modules, and water quality on Escherichia coli (E. coli) disinfection and decrease of COD and $UV_{254}$ absorbance were investigated. Results: The experimental results showed that at a voltage of over 80 V, most of the E. coli were disinfected within 90 seconds. E. coli inactivation was not affected by the air flow rate. E. coli disinfection in the multiplasma process showed the traditional log-linear form of the disinfection curve. E. coli inactivation performance by transformer 3-Reactor 5 and transformer 3-Reactor 3 were similar. The disinfection performance of the UV process was affected by artificial sewage water. However, the plasma process was less affected by the artificial sewage within the standards for effluent water quality. Conclusions: Disinfection performance with several low voltages and plasma modules of three to five in number applied to the plasma process was higher than that concentrating a small amount of high voltage through a single plasma reactor. Removal of COD, $UV_{254}$ absorbance, and E. coli disinfection with the plasma process were better than with the UV process.

Pilot 플라즈마 반응기를 이용한 하수 중 미생물의 불활성화

김동석,박영식,Kim, Dong-Seog,Park, Young-Seek 한국환경보건학회 2013 한국환경보건학회지 Vol.39 No.3

Objectives: For the field application of the dielectric barrier discharge plasma reactor, scale-up of the plasma reactor is needed. This study investigated the possibility of inactivation of microorganisms in sewage using pilot multi-plasma reactor. We also considered the possibility of degradation of total organic carbon (TOC) and nonbiodegradable matter ($UV_{254}$) in sewage. Methods: The pilot plasma reactor consists of plasma reactor with three plasma modules (discharge electrode and quartz dielectric tube), liquid-gas mixer, high voltage transformers, gas supply equipment and a liquid circulation system. In order to determine the operating conditions of the pilot plasma reactor, we performed experiments on the operation parameters such as gas and liquid flow rate and electric discharge voltage. Results: The experimental results showed that optimum operation conditions for the pilot plasma reactor in batch experiments were 1 L/min air flow rate), 4 L/min liquid circulation rate, and 13 kV electric discharge voltage, respectively. The main operation factor of the pilot plasma process was the high voltage. In continuous operation of the air plasma process, residual microorganisms, $UV_{254}$ absorbance and TOC removal rate at optimal condition of 13 kV were $10^{2.24}$ CFU/mL, 56.5% and 8.6%, respectively, while in oxygen plasma process at 10 kV, residual microorganisms, $UV_{254}$ absorbance and TOC removal rate at optimal conditions were $10^{1.0}$ CFU/mL, 73.3% and 24.4%, respectively. Electric power was increased exponentially with the increase in high voltage ($R^2$ = 0.9964). Electric power = $0.0492{\times}\exp^{(0.6027{\times}lectric\;discharge\;voltage)}$ Conclusions: Inactivation of microorganisms in sewage effluent using the pilot plasma process was done. The performance of oxygen plasma process was superior to air plasma process. The power consumption of oxygen plasma process was less than that of air plasma process. However, it was considered that the final evaluation of air and oxygen plasma must be evaluated by considering low power consumption, high process performance, operating costs and facility expenses of an oxygen generator.