ISO/IEC 18000-6 Type-B RFID 리더의 태그 응답신호 검출 성능 향상

최우석,서기환,김형남,Choi, Woo-Seok,Suh, Ki-Hwan,Kim, Hyoung-Nam 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.1C

본 논문에서는 ISO/IEC 18000-6 Type-B RFID 시스템에서 태그 응답신호, 즉 리더 수신신호에서 허용오차 (Tolerance)와 잡음이 미치는 영향에 대해서 알아보고, 이에 대한 영향을 최소화하는 방법을 제안한다. 제안된 방법은 오버 샘플링된 수신 신호를 가지고 가변천이검출윈도우를 이용하여 허용오차에 의한 영향을 제거하고 비트가 천이되는 위치를 검출하며, 이전의 비트 천이에서 현재 비트 천이까지의 윈도우 내 수신 신호를 평균하여 잡음의 효과를 줄인다. 제안된 방법을 적용하여 자체 제작한 리더에서 성능 테스트한 결과를 상용리더와의 비교 실험결과로 제시한다. This paper proposes a windowing method to reduce noise effect and bit synchronization error caused by tolerance of a tag-response signal for ISO/IEC 18000-6 type-B readers. A tag response signal has very weak power because of a back-scattering modulation scheme and thus may be sensitive to noise. In addition, bit tolerance admitted in a tag response signal requires robust timing synchronization because it affects readers' detection performance. To reduce the two undesirable effects in a tag signal, we acquire bit transition position by using variable windows from over-sampled data, and average whole data in one bit duration. With a hardware system adopting the proposed method, we tested and verified its performance.

가리비(Patinopecten yessoensis) 및 키조개(Atrina pectinata)의 부위별 중금속 함량 및 위해도 평가

최우석,윤민철,조미라,권지영,김지회,이희정,김풍호,Choi, Woo Seok,Yoon, Minchul,Jo, Mi Ra,Kwon, Ji Young,Kim, Ji Hoe,Lee, Hee jeung,Kim, Poong Ho 한국수산과학회 2017 한국수산과학회지 Vol.50 No.5

Recent years have seen steadily increasing concerns about human exposure to heavy metals through seafood consumption. In Korea, the diverse dietary patterns of different bivalve shellfish necessitate tissue-specific evaluation of heavy metal contents for risk assessment. We analyzed the heavy metal contents of various tissues in scallops (Patinopecten yessoensis) and pen shells (Atrina pectinate). In both species, we found higher levels of cadmium (Cd) in the mantle than in the adductive muscle, while there was no significant difference between the two tissue types in total mercury (THg) and lead (Pb) (P<0.05). Levels of THg and Pb were acceptable by Korean standards. However, the level of Cd in pen shell mantle tissue exceeded the standard by 40%. The rate of heavy metal exposure from consumption of these species was shown to be 0.003-0.010% of the provisional tolerable weekly intake of THg and 0.312-0.600% of the provisional tolerable monthly intake (PTWI) of Cd as recommended by the Joint FAO/WHO Expert Committee on Food Additives. These findings on the tissue-specific heavy metal contents of these species will be useful in assessing the health risks of Korean dietary habits.

Neuroimaging of Traumatic Brain Injury

최우석,Choi, Woo Suk The Korean Society of Biological Psychiatry 1995 생물정신의학 Vol.2 No.2

두부 외상은 많은 발생율과 사망율을 차지하고 있으며, 건강한 생활을 위해 큰 관심을 갖게 되었다. 신경방사선영상은 외상성 뇌손상 환자들의 진단과 치료에 필수적인 방법이다. 뇌손상의 기본 기전, 병리, 그리고 영상 소견을 이해 하는 것은 매우 중요하다. 1970년대에 Glasgow coma scale의 형상과 전산화단층촬영(CT)의 발달은 임상의사들이 두부외상에 대한 평가와 환자들의 경과를 예상하는데 극적인 변화를 주었다. 최근 자기공명영상(MRI)의 발달로 외상성 뇌손상의 형태를 더욱 이해 하게 되었고, 두부 외상의 발견율이 높아지게 되었다.

표층황반원공에서 수술적 치료의 결과

최우석,김상원,이우석,문상정,윤희성,Woo Seok Choi,Sang Won Kim,Woo Seok Lee,Sang Jeong Moon,Hee Seong Yoon 대한안과학회 2012 대한안과학회지 Vol.53 No.9

Purpose: To investigate the visual and anatomical results of surgical treatment for symptomatic lamellar macular hole. Methods: Ten eyes of ten patients with decreased visual acuity and lamellar macular hole were diagnosed using optical coherence tomography (OCT). Pars plana vitrectomy, epiretinal membrane removal, internal limiting membrane peeling, and gas tamponade (5 eyes) were performed for the treatment of lamellar hole. The resolution of the lamellar hole was assessed in relation to each OCT image at baseline. Results: The mean postoperative follow-up duration was 7.5 months, and best corrected visual acuity improved from log MAR 0.67 ± 0.38 to log MAR 0.30 ± 0.28. Central foveal thickness decreased from 441 ± 184 μm to 291 ± 64 μm. The OCT of all eyes demonstrated improvement in macular contour. However, retinal detachment in one eye occurred at two months after the operation and was reattached with gas tamponade and photocoagulation. Conclusions: Vitrectomy, epiretinal membrane removal and internal limiting membrane peeling showed benefit in the treatment of symptomatic lamellar macular hole. However, large and prospective studies are necessary regarding the surgical indication, time and procedure for lamella macular hole. J Korean Ophthalmol Soc 2012;53(9):1291-1295

인쇄용 페이스트의 조성변화가 탄소나노튜브 캐소드의 전계방출 특성에 미치는 영향

최우석,신허영,김동희,안병건,정원섭,이동구,조영래,Choi, Woo-Suk,Shin, Heo-Young,Kim, Dong-Hee,Ahn, Byung-Gun,Chung, Won-Sub,Lee, Dong-Gu,Cho, Young-Rea 한국재료학회 2003 한국재료학회지 Vol.13 No.10

The effects of paste materials on field emission properties in a carbon nanotube(CNT) cathode were investigated for high-efficient field emission displays. The major components in CNT paste for screen printing were a metallic Ag-paste, a dielectric glass-frit and CNT ink. The emission current from the cathode by an electron tunneling effect increased with an increase in the dielectric material fraction in the CNT paste, which is related to an increase of field enhancement factor in Fowler-Nordheim equation. The surface treatment used, after soft baking of the screen-printed CNT films, greatly affected the decrease in the turn-on field in CNT cathode and the uniformity of emission sites over the entire CNT film area.

유수정체용 홍채고정안내렌즈삽입술 후 각막내피세포의 2년 변화

최우석,최봉준,허준,Woo Seok Choi,Bong Joon Choi,Jun Her 대한안과학회 2008 대한안과학회지 Vol.49 No.2

`Purpose: To investigate quantitative and morphometric endothelial changes in phakic eyes implanted with an iris-fixed phakic intraocular lens in Korean patients. Methods: We prospectively examined the endothelial cell density (ECD), ECD loss (ECL), coefficient variations (CV), and frequency of Hexagons (6A) in 46 phakic eyes implanted with an iris-fixed phakic intraocular lens. The effect of anterior chamber depth (ACD) and diopter of iris-fixed phakic intraocular lens on ECD was statistically analyzed. Results: Preoperative mean ECD was 2923±257 cells/mm2. ECL at postoperative 1, 3, 6, 12, and 24 monthswas 0.71%, 0.88%, 0.70%, 0.64%, and 2.34%. It was significant only in the month 24 results. The mean CV value at the same time was 0.343, 0.342, 0.334, 0.329, 0.326, and 0.338. The change was significant at the 12th month. The mean 6A value at the same time was 58.2%, 57.8%, 59.7%, 59.6%, 60.1%, and 58.8%. There was no significant change in 6A value. Preoperative ACD and diopter of iris-fixed phakic intraocular lens didn't affect the ECD change. Conclusions: This two-year follow-up study of changes in endothelial cells after implantation iris-fixated phakic intraocular lens showed statistically significant decreases in the cells, which is not very significant considering the physiologic reduction rate of the cells. Thses decreases showed a tendency to be stabilized with recovery of morphological changes. Further long-term follow-up is needed to determine its long-lasting effect.`

근시 교정에서 안내후방콘택트렌즈 삽입술과 홍채고정렌즈 삽입술의 임상성적 비교 연구

최우석,이호영,서성관,허준,Woo Seok Choi,M,D,Ho Young Lee,M,D,Sung Guan Seo,M,D,Jun Her,M,D,Ph,D 대한안과학회 2008 대한안과학회지 Vol.49 No.9

Purpose: We compared the results of implanting an implantable contact lens (ICL) and an iris claw lens (Artisan® lens) in patients’ wtih myopia and sought to determine a basis for choosing between the two lenses. Methods: ICLs were implanted in 32 eyes of 18 patients, and Artisan® lenses were implanted in 40 eyes of 23 patients. Uncorrected visual acuity, refraction, endothelial cell density, intraocular pressure, and slit lamp measurements were taken for 12 months. Results: All the patients had improved UCVA from the day after the operation until the 12th month. The mean spherical equivalent refraction at postoperative month 12 was -0.78±0.54D in the ICL group and -0.78 ±0.59D in the Artisan® lens group. In the same period, endothelial cell density loss was 5.34% in the ICL group but was not significant in the Artisan® lens group. There were no significant complications in either group. Conclusions: Both ICL and Artisan® lens implantation resulted in immediate visual improvement and stability of vision during the follow-up period. There was no significant difference in post-operative results. Further study will be needed to decide which lens is the better choice for delicate conditions in myopic patients. J Korean Ophthalmol Soc 2008;49(9):1406-1414

함수비를 고려한 모래의 상대밀도 추정을 위한 Fall Cone 관입량의 적용

최우석,손영환,박재성,노수각,봉태호,Choi, Woo-Seok,Son, Young-Hwan,Park, Jae-Sung,Noh, Soo-Kack,Bong, Tae-Ho 한국농공학회 2012 한국농공학회논문집 Vol.54 No.5

Relative density, used to express dynamics condition of sand quantitatively, is measured by RI Test, Standard Penetration Test and Cone Penetration Test. Each measurement method has demerits, which is complicated or needs a specific analysis instrument and an analysis of expert. Also the ground is in wet condition commonly because of an unsaturated zone between a saturated zone and a surface, so the behaviour of the ground has different engineering properties unlike the dry ground and it diminishes accuracy of measuring relative density. In this study, the correlation between relative density and penetration of fall cone test in dry condition and wet condition with variation of water content was analyzed and a simple measuring method for relative density was suggested. As a result, there were difference of penetration between dry sands and wet sands, the correlation between relative density and penetration showed linear expression and relative density could be measured by the linear relation.

뇌동맥확장증에 대한 전산화단층촬영소견

최우석,고영태,임재훈,이선화,윤엽,이동호,임언,이봉암,김국기,김광명,김태성,Choi, Woo-Suk,Ko, Young-Tae,Lim, Jae-Hoon,Lee, Sun-Wha,Yoon, Yup,Lee, Dong-Ho,Leem, Won,Rhee, Bong-Arm,Kim, Gook-Ki,Kim, Kwang-Myung,Kim, Tae-Sung 대한영상의학회 1987 대한영상의학회지 Vol.23 No.1

The computed tomographic findings of cerebral arterial ectasia in 8 patients, of which 5 cases were angiographically documented, are reported. The ectatic arteries, located predominantly in the suprasellar and interpeduncular cisterns, appeared as serpiginous, tubular structures on the unenhanced scan. The enhanced CT scan demonstrated dense, sharply defined, homogeneous intraluminal enhancement. Until recently, the diagnosis of cerebral arterial ectasia was usually established by angiography. With introduction of CT it has become possible to noninvasively indentify and characterize this vascular disorder and its associated intracranial complications. The vertebrobasilar dolichoectasia may be diagnosed by CT as an extra-axial lesioin in the cerebellopontione angle. It enhances in a tubular fashion after intravenous injection of contrast.

현토고본환이 노화유발 백서의 항산화능에 미치는 영향

최우석,강석봉,Choi, Woo-Suk,Kang, Seok-Bong 대한한방내과학회 2004 大韓韓方內科學會誌 Vol.25 No.4

Objectives : This experiment was done to evaluate the effects of Hyuntogobon-hwan(HTG) on antioxidant capability and lipidic concentration in blood, both of which are presumed to be related to aging. Methods : 12 week-old SD rats were divided into controlled group, uncontrolled group and HTG group. As controlled and HTG groups were given subcutaneous injection of D-galactose(50mg/kg/rat), at the same time HTG group was administered extract of Hyuntogobon-hwan(270mg/200g). HTG injections continued for 6 weeks. After initial injections, blood was drawn from each group and the following were measured: the activity of SOD, GSH-px, catalase in erythrocytes, TSARS value, concentration of total lipid, tryglyceride in blood plasma. Results : The activities of SOD and GSH-px in erythrocytes increased significantly in HTG group compared with controlled group. The activity of catalase seemed to increase slightly, but it was barely noticeable. The concentration of total lipid in plasma decreased significantly in HTG group compared with controlled group. The value of TBARS in plasma seemed to decrease slightly, but it was barely noticeable. Conclusions : According to the above results, Hyuntogobon-hwan has an influence on aging by virtue of activation of antioxidative enzyme systems in erythrocytes and concentrations of lipid in blood plasma.