OFDM 시스템을 위한 Radix-8/4/2 FFT 프로세서

박정민,김영진,이현수 경희대학교 경희정보통신 SoC연구소 2008 경희정보통신SOC연구소 논문집 Vol.9 No.-

In this paper, we propose an efficient variable-length radix-8/4/2 FFT architecture for OFDM systems. The FFT processor is based on radix-8 FFT algorithm and also supports radix-4 or radix-2 FFT computation. A radix-8/4/2 butterfly unit computes radix-8 FFT algorithm basically. If it cannot run radix-8 FFT algorithm at last stage then it computes radix-4 or radix-2 FFT algorithm. Furthermore, proposed FFT architecture use shared-memory to minimize and simplify hardware. We are using efficient "In-place" memory access method to maintain conflict-free data access and minimize memory size. The design consider seven different FFT lengths including 64, 256, 512, 1024, 2048, 4096 and 8192 points which cover all the required FFT lengths by 802.11a, 802.16a. DAB, DVB-T, VDSL and ADSL.

강원도 삼척지역의 스멕타이트질 점토의 산상 및 특성

황진연,박성완,이상현,최수용 부산대학교 기초과학연구소 1995 부산대학교 기초과학연구소 연구논문집 Vol.15 No.-

The smectite-rich clays were found locally in Paleozoic calcareous sedimentary rocks in the Samcheok area. Their occurrences were investigated in detail, and the physico-chemical properties of the clays were also determined by X-ray diffraction, chemical analysis, thermal analysis and cation exchanging experiment. The smectitie clays occur as the fissure filling dyke developed in calcareous semimentary rock and as alteration products of instrusive rhyolite. Most of clays occur at the contact between the sedimentary rock and the rhyolite, and the alteration zone was observed only in rhyolite body close to the contact. Judging from their occurrences, it is believed that the smectite-rich clays in this area were formed by the hydrothemal alteration. The smectite clays from the area are mainly composed of Ca-montmorillinite, and associated with small quantities of quartz, opal-CT and feldspar. The montmorillinites from this area lower in Fe content, and higher in exchangeable Ca ion, compared to those of bentonite from the Yangnam-Yeongil area.

관상동맥질환 환자에서 스텐트 시술 후 재협착에 관한 연구

강진환,권영주,박상호,한대희,이상철,김명구,변정득,최병조,심규혁,온영근,현민수,김성구 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background and aims : In the coronary artery disease, a rate of restenosis was much decreased by placement of coronary stent than when percutaneous transluminal coronary angioplasty has been applied, but there are still important clinical problems of restenosis. There has been many progressive studies about various factors contributed to this restenosis. So, we studied a relation between restenosis after placement of coronary stent in the coronary artery disease and many clinical factors, characteristics of stenotic lesion and procedural factors, and also assessed the restenosis rate of various coronary stents. Methods : Total 58 lesions(46 cases of patients ; man 30, woman 16) were evaluated, which has been performed a follow-up coronary angiography after 6 months (mean 188 days) since coronary stent had been placed. Various stents were implanted and assessed a relation between restenosis and many factors. Results : Of 58 lesions were target stenotic studies, there were 22 of restenotic lesions(37.9%), and the restenosis rate wes statistically significant difference in the relation with diabetes mellitus(p<0.05), group of acute myocardial infarction(p<0.05) among clinical diagnosis of ischemic heart disease(stable angina, unstable angina and acute myocardial infarction) in clinical factors and with high dilation pressure of stent(p<0.05) in procedural factors. When the rate of restenosis was evaluated among implanted stents, it was lowest in the Multilink^(®) stent and highest in the Nir Royal^(®) stent(60%). Conclusion : In this study of restenosis and various factors after placement of stents in the coronary artety disease, factors such as diabetes mellitus, group of acute myocardial infarction and a dilation pressure of stent were significant related with restenosis and the restenosis rate of Multilink^(®) stent was lowest and the highest restenosis rate was of Nir Royal^(®) stent.

열탈착 분석법에 의한 Pt(111) 표면위의 NO와 CO의 흡착

이순보,박종윤,곽현태,부진효,강용철 성균관대학교 1992 論文集 Vol.42 No.2

The adsorptions of nitric oxide and carbon monoxide on Pt(111) surfaces have been studied by using LEED, AES, and TDS(Thermal Desorption spectroscopy). The adsorbed species of NO is predominantly molecular on the Pt(111) surface at room temperature. A main desorption peak of TDS is attributed to the molecular adsorption at 360K. With increasing No exposures, a shoulder peak at 480K which may be attributed to the defect site adsorption is appeared. The desorption rate order for No desorption is 1st order and the desorption energy for NO calculated by Redhead equation assuming pre-exponential factor v_1=10^13 sec^-1 is 21.7Kcal/mol. The adsorption of carbon monoxide is also molecular on Pt(111) surface at room temperature. The TDS results showed only a single broad peak at 460K, which is attributed to molecular adsorption. The desorption order for CO desorption is 1st order as well as NO and the desorption energy for CO is 28Kcal/mol.

초고진공 장치의 설계 및 제작과 LEED Optics에 의한 Auger Electron Spectrometer의 분해능 측정

이순보,박종윤,곽현태,부진효,이성용 성균관대학교 1992 論文集 Vol.42 No.2

A multipurpose Ultra High Vacuum chamber was designed and constructed in this laboratory. This enables us to be equipped with various analytical instruments such as Ar-ion gun LEED optics, Electron analyzer, and Quadrupole mass spectrometer etc. The 4-Grid LEED optics, a product of Omicron company in West Germany, was equipped with the UHV chamber and the LEED power supply was designed by this group. Turbo-C language figured out Auger spectra of the ad-species by means of the computer interface. The resolution of Auger electron spectrometer was measured with a constant primary electron beam energy. The results showed that the resolution was independent of the primary electron beam energy, but depends on the modulation voltage. Also, it was revealed that the resolution of 4-Grid optics was more improved than that of 3-Grid optics.

Ar 이온에 의해 Sputtering된 Pt(111) 표면의 NO 흡착

이순보,부진효,이성용,박종윤,곽현태 성균관대학교 기초과학연구소 1992 論文集 Vol.43 No.1

Adsorption of nitric oxide on the Pt(111) surface sputtered by Ar-ion has been studied using thermal desorption spectroscopy, Auger electron spectroscopy, and low energy electron diffraction. A thermal desorption spectrum obtained from the perfect Pt(111) saturated with NO at 300K is quite simillar to those reported previously. The main portion desorbs at about 370K(α-state) with a shoulder at about 470K(β-state). The chemisorption of nitric oxide is predominantly molecular on the Pt(111) surface, accompanied by a small amount of dissociation which becomes negligible when the Pt(111) surface is perfect. When the Pt(111) surface is sputtered by Ar-ion with 2KeV, the thermal desorption spectrum becomes quite complex. The shoulder peak, which appears on the perfect surface spectrum, increases with Ar-ion sputtering time. The maximum desorption spectra of N₂ and N₂O are observed simultaneously between 470 and 600K. The desorption mechanisms for N₂O are proposed. The increasing N₂ with the β-state of NO indicates that the β-state is a precursor to the NO dissociation.

만성 심부전환자의 혈액에서 측정한 Tumor necrosis factor-α 및 Interleukin-6의 임상적 의의

김명구,김성구,박상호,한대희,강진환,변정득,심규혁,최병조,방덕원,온영근,현민수,권영주 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background and objectives: Many conditions are responsible for the pathophysiology and progressive mechanisms of congestive heart failure. More recently, it has also become evidence that another class of biologycally activated molecules generically reffered to as cytokine these are also over expressed in congestive heart failure. Therefore, the purpose of this study was to measure concentrations of tumor necrosis factor-α(TNF-α), interleukin-6(IL-6) in mild to severe symptoms of heart failure and compare their values with those found in normal control and analysed correlation relationship between cytokine level, clinical findings and hemodynamic indicies. Subjects and Methodology: Levels of TNF-α and IL-6 were measured on pulmonary artery during cardiac catheterization in heart failure patients(n=32) and normal subjects(n=8) as well as physical examination and echocardiogram. Cytokines assay were performed on plasma using commercially available ELISA(Enazyme-Linked Immunosorbent Assay) kits. Results: Although the levels of TNF-α and IL-6 tend to increase in congestive heart failure group, the cytokines level was not made significantly statistical difference between congestive heart failure group and controls. When analyzing the correlation between the levels of PCWP(pulmonary capillary wedge pressure) and cytokines(TNF-α, IL-6), respectively, there were statistically significant correlation coefficient 0.32,(p<0.05), 0.39(p<0.01). The cytokine IL-6 and pressure of pulmonary artery were significant correlation.(correlation coefficient 0.36, p<0.02) More significantly, there was correlated with TNF-α and IL-6.(correlation coefficient 0.57, p<0.001) Conclusions: There was tended toward high concentration of TNF-α & IL-6 in congestive heart failure and significant difference for PCWP between TNF-α & IL-6, thus may be correlated with development and progression in congestive heart failure.

허혈성 심질환에서 염증지표에 관한 연구

번정득,권영주,박상호,한대희,이상철,강진환,김명구,심규혁,최병조,온영근,현민수,김성구 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

Background : Atherosclerosis is the chief underlying cause of ischemic heart disease and there is increasing evidence that inflammation is an important determinant of the development of atherosclerosis. We assessed the levels of inflammatory markers in patients with ischemic heart disease and normal group who has normal coronary angiograms. Materials and Methods : Coronary angiography was performed in 142 patients. 107 patients of ischemic heart disease(stable angina pectoris 58, unstable angina pectoris 30, Acute myocardial infarction 19) and 38 normal control subjects. We assessed the level of inflammatory markers, such as CRP, ESR, fibrinogen and leukocyte. Results : CRP, ESR and fibrinogen values of the patients with stable angina pectoris and unstable angina pectoris were higher than that of normal control group, but there were no statistical significance. Leukocyte value of the patients with unstable angina pectoris(9003.3±701.5/mm^(3)) was significantly higher than that of the patients with stable angina pectoris(6685.5±245.8/mm^(3)) and normal control subjects(6394.3±235.1/mm^(3)). CRP, ESR and fibrinogen values of the patients with acute myocardial infarction were also higher than that of normal control subjects. CRP was 3.88±2.05 mg/dL in acute mocardial infarction group, and 0.29±0.15 mg/dL in normal control subject group(p<0.05). Fibrinogen was 541.6±45.1 mg/dL in acute myocardial infarction group, 321.4±25.6 mg/dL in normal control subject group(p<0.05). Leukocyte was 10942.1±737.6/mm^(3) in acute myocardial infarction group, 6394.3±235.1/mm^(3) in normal control subject group(p<0.05). Conclusions : This study demonstrate that CRP, fibrinogen and leukocyte values of acute myocardial infarction group were significantly higher than that of control group and stable, unstable argina pectoris group. Leucokyte values were significantly elevated in unstable angina group, but CRP values were not in unstable angina group.

Benzoyl peroxide의 환경에서의 초기 위해성 평가

김미경,배희경,김수현,송상환,구현주,박광식,이문순,전성환,나진균 한국환경독성학회 2004 환경독성보건학회지 Vol.19 No.1

Benzoyl peroxide is a High Production Volume Chemical, which is produced about 1,375 tons/year in Korea as of 2001 survey. The substance is mainly used as initiators in polymerization, catalysts in hte plastics industry, bleaching agents for flour nad medication for acne vulgaris. In this study, quantitative Structure-Activity Relationships(QSAR) are used for getting adequate information on the physical-chemical properties of this chemical. And hydrolysis in water, acute toxicity to aquatic and terrestrial organisms for benzoyl peroxide were studied. The physical-chemical properties of benzoyl peroxide were estimated as followed; vapor pressure=0.00929 pa, Log K_(ow)=3.43, Henry's Law constant=3.54×10^(-6) atm-m³/mole at 25℃, the half-life of photodegradation=3days and bioconcentration factor(BCF)=92. Hydrolysis half-life of benzoyl peroxide in water was 5.2hr at pH 7 at 25℃ and according to the structure of this substance hydrolysis product was expected to benzoic acid. Benzoyl peroxide has toxic effects on the aquatic organisms. 72 hr-ErC_(50)(growth rate) for algae was 0.44mg/L, 48hr-EC_(50) for daphnia was 0.07mg/L and the 96hr-LC_(50) of acute toxicity to fish was 0.24mg/L. Acute toxicity to terrestrial organisms(earth worm) of benzoyl peroxide was low(14 day-LC_(50)=>1,000mg/kg). Although benzoyl peroxide is high toxic to aquatic organisms, the substance is not bioaccumulated because of the rapid removal by hydrolysis (half life=5.2hr at pH 7 at 25℃) and biodegradation(8.% by BOD after 21days). The toxicity observed is assumed to be due to benzoyl peroxide rather than benzoic acid, which shows much lower toxicity to aquatic organisms. One can assume that effects occur before hydrolysis takes place. From the acute toxicity value of algae, daphnia and fish, an assessment factor of 100 was used to determine the predicted no effect concentration(PNEC). The PNEC was calculated to be 0.7㎍/L based on the 48hr-EC_(50) daphnia(0.07mg/L). The substance shows high acute toxicity to aquatic organisms and some information indicates wide-dispersive use of this substance. So this substance is a candidate for further work, even if it hydrolysis rapidly and has a low bioaccumulation potential. This could lead to local concern for the aquatic environment and therefore environmental exposure assessment is recommended.

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1996)

김재홍,황동규,전재홍,김윤석,김중환,김용준,이창균,임동진,김현수,조창근,김경문,박상훈,전우형,김희성,이호정,차명수,김갑형,김형석,김석우,황지환,박병순,권오상,이민수,송기훈,성소영,이인섭,부태성 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.2

Background : In recent years, gonorrhea has been panedemic and remains one of the most commom STDs in the world, especially in developing countries. Objective & Methods: For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results: In 1996, 139 strains of N. gonorrhoeae were isolated, among which 53(39.0%) were PPNG. Conclusion: Our results suggests that after a peak of 74.3% in 1993, the prevalence of PPNG in Seoul is gradually declining.