다기지국 환경에서 전자파 노출량

조의현(Euy-Hyun Cho),박정규(Jeong-Kyu Park) 한국콘텐츠학회 2011 한국콘텐츠학회논문지 Vol.11 No.9

본 연구는 기지국 설치 건물의 층별 전자파 강도가 인체에 유해한지, 그리고 예측 가능한지를 조사하기 위해 수행되었다. 조사는 산란체가 많은 기지국과 산란체가 적은 기지국을 선별하여 실험을 하였다. 실험은 국제 규격과 국내 TTA 표준을 모두 충족시키기 위해, 기지국이 설치된 건물의 층별로 세가지 높이(1.1m,1. 5m,1.7m)를 기준으로 하여 각 높이에서 3개의 위치에서 전자파 강도의 실효값(rms)이 측정되었다. 9개의 위치에서 측정된 주파수별 실효값(rms)의 Max가 전자파 인체 보호 기준대비 최대 48.12%(옥상 측정값)로 주파수별로 인체보호 기준을 만족함을 확인하였다. 그리고 산출된 주파수 별 노출지수 합도 최대 0.1445로 기준 1대비 최대 7배 이상 낮은 수준임을 확인하였다. 기지국별, 층별 조건에서는 868MHz, 2.14GHz의 전자파 강도 모두 P>0.005로 유의하였으며, R-Sq(조정)값이 50% 이상값을 보여서 회귀 방정식이 데이터의 정보를 충분히 흡수하고 있다는 것을 확인하였다. 그러나 기지국 데이터 통합, 층별 데이터 통합 조건에서는 868MHz, 2.14GHz의 전자파 강도 모두 P>0.05 이지만, 868MHz 전자파 강도의 R-Sq(조정)값이 50%이하값(34.15%)을 보여서, 868MHz 전자파 강도는 기지국이 설치된 환경에 많은 영향을 받는 것을 확인 할 수 있었다. 2.14GHz의 전자파 강도는 R-Sq(조정)값이 50% 이상(51.8%)를 보여서 2.14GHz의 전자파 강도의 회귀방정의 모형은 적합하였으며, 기지국이 설치된 건물의 주변 환경에 크게 영향을 받지 않고, 기지국 설치 건물의 층별 전자파 강도를 회귀 방정식으로 예측 할 수 있었다. The Study was carreid out to see whether the intensity of electromagnetic waves in each floor of a building where the sharing base station has been established is harmful to a human body, and to expect the intensity of the waves in the building. The investigate was performed on both of sharing base station either with many scatterers or without any of them. To satisfy the international standard and the domestic TTA standard, ms for each of the electromagnetic wave of every floor in the building with the station was measured from 3 location of 3 heights(1.1m,1.5m, and 1.7m). Max of the measured rsm from the each of the frequencies in the nine location was confirmed to be 48.12%(the rooftop measured value) at most, compared to the human body protection standard. The value was confirmed to satisfy the human body protection standard for each frequency. And the total value of the calculated exposure indexes for each frequency was determined to be more than 7 times lower at most, which was 0.1445, compared to the 1 standard. Since P value in both of 868MHz and 2.14GHz electromagnetic waves intensity for each base station and floor was less than 0.05, it was revealed to be meaningful, and since R-Sq(adj) value showed a value more than 50%, the regression equation was determined to fully absorb the data information. However, although the P value of both of 868MHz and 2.14GHz electromagnetic waves intensities under the integrating terms of the base station data and the floor data was showed to be less than 0,05, since R-Sq(adj) value of 868MHz electromagnetic waves intensity presented a value smaller than 50%(34.15%), it was determined that the 868MHz electromagnetic waves intensity is very much influenced by an environment with a base station. Because the electromagnetic waves intensity of 2.14GHz show R-Sq(adj) value bigger then 50%(51.8%), The regression equation model of 2.14GHz electromagnetic waves intensity was confirmed to be proper. It also turned out not to be effected by the surrounding environment near a building with the base station and the intensity of electromagnetic waves for each floor of such building was expectable by the regression equation.

PC 사용 환경의 2.5 인치 하드디스크의 가속 수명 시험

조의현(Euy-Hyun Cho),박정규(Jeong-kyu Park),서희돈(Hui-Don Seo) 한국디지털콘텐츠학회 2014 한국디지털콘텐츠학회논문지 Vol.15 No.1

In order to estimate the life of 2,5 inch HDD which is adopted by PC environment, make the test plan which reflect the failure mode of market, make the test model of accelerated life test which reflect the stress of temperature. after an analysis of the environment of PC using, test procedure was decided that operation was write 50 % and read 50 %, and then access method was sequential 50 % and random 50%. The acceleration life test was executed on condition that temperature was 50°C and 60°C, performance was 95 % in max performance, test time was 1000 hours. by the test of goodness of fit of anderson-darling of the failure data during test, it was confirmed that the distribution of failure fellow weibull. test for shape and scale was equal, and shape parameter was 0.7177, characteristic life was 429434 hours at normal user condition(30 °C) by the analysis of weibull-arrhenius modeling. It made no difference about the statistics when equality test was executed. The activation energy was 0.2775eV. In analyzing between the failure samples of acceleration test and the samples of market return even though there is detail difference about the share of failure mode, the rank of share was almost same. This study suggest the test procedure of acceleration test of 2.5 inch HDD in PC using environment, and help the life estimation at manufacture and user

PC 사용 환경에 기반한 2.5 인치 하드 디스크의 수명주기 예측에 대한 연구

조의현(Euy-Hyun Cho),박정규(Jeong-Kyu Park),이민우(Min-woo Lee),권순무(Soon-Mu Kwon) 한국디지털콘텐츠학회 2014 한국디지털콘텐츠학회논문지 Vol.15 No.2

The mass storage of data and the importance of storage capacity lately has emerged. In this paper, we suggest the new method which estimate life cycle from acceleration life test about 2.5 inch hard disk driver as mass storage, which minimize the difference between real market annual failure rate and estimated failure rate. we obtain market transfer capacity per hours from returned 2.5inch hard disk drives about 309 numbers and accelerating transfer capacity per hours from acceleration life test. we calculate acceleration factor about duty cycle and estimate annual failure rate from failure rate and acceleration factors: temperature acceleration factor, duty cycle acceleration factor, the transfer capacity per hour represent the 93.4 % of user is 5.8 GB/hour, the transfer capacity per hour from acceleration life test is 81.4 GB/hour. the acceleration factor of duty cycle is 14.1. annual failure rate is stabilized at market one year after, annual failure rate is between 0.3 and 0.378. estimated annual failure rate is 0.4, so it is matched at 75~94 % between estimate annual failure rate and market annual failure rate. This study influence the estimate method of annual failure rate by the result of acceleration life cycle of manufacture.

PACS 환경에서 하드디스크의 가속 수명시험

조의현(Euy-Hyun Cho),박정규(Jeong-kyu Park),채종규(Jong-Gyu Chae) 한국디지털콘텐츠학회 2015 한국디지털콘텐츠학회논문지 Vol.16 No.1

In this paper, we estimate the life cycle from acceleration life test about the hard disk of disk array of image storage of PACS. Webuil distribution was selected by the Anderson-Darling goodness-of-fit test with data of down time at 50 ˚C and 60 ˚C. The equality test of shape parameter and scale parameter was conducted, so that the probability distribution estimated from data of down time at 50 ˚C and 60 ˚C was not statistically significant. The shape parameter was 1.0409, The characteristic life was 24603.5 hours at normal user condition(30 °C) by the analysis of weibull-arrhenius modeling which included the acceleration factor of temperature, and The activation energy was 0.5011 eV through arrhenius modeling. The failure analysis of the failure samples of acceleration test and the samples of market return was conducted, so that the share percentage of failure mode was detail difference but the rank of share percentage was almost same. This study suggest the test procedure of acceleration test of hard disk drive in PACS using environment, and help the life estimation at manufacture and use.

전자기식 체외충격파쇄석술시 하부요관 결석 환자에 대해 적합한 충격강도와 C-arm 총 가동시간

박정규(Jeong kyu Park),조의현(Euy Hyun Cho) 한국방사선학회 2014 한국방사선학회 논문지 Vol.8 No.7

체외 충격파 쇄석술시 쇄석기종에 따라 각각 장단점이 있으며, 전 처치로 인한 여러 가지 부작용이 보고되고 있다. 이에 전자기식 ESWL시 하부결석환자에서 적합한 충격파의 강도를 찾아보고, C-arm의 총 가동시간을 측정해 보았다. 본 연구는 2014년 1월부터 6월까지 경북지역 일개시의 C대학병원에서 전 처치를 시행하지 않고 ESWL을 받은 65명의 환자를 대상으로 하였다. 성비는 남자가 48명, 여자가 17명으로 남자가 더 많았으며, 연령은 50대가 가장 많았다. 하부요로결석의 발생은 왼쪽이 더 많았으며, 결석의 크기는 5mm 이하가 39명으로 가장 많았다. 적합한 충격강도는 1의 강도이며 통증을 호소하는 경우 C의 강도로 전환하여 충격을 가할 수 있다. 또한 C-arm의 총 가동시간은 241.73±30.37초로 나타났으며, 이것은 하부요로결석의 크기와 유의한 차이를 보였다(p<0.05). 따라서, ESWL시 전 처치를 시행하지 않고 시술을 할 경우 요관 결석의 부위에 따라 적합한 충격강도와 충격빈도의 기준이 필요로 하며, C-arm 총 가동시간도 요관 결석의 발생부위에 따라 방사선으로 인한 피폭을 최소화하기 위한 총 가동시간에 대한 기준이 필요할 것으로 사료된다. The advantages and disadvantages of the various models of crushed ESWL (Extracorporeal Shock Wave Lithotripsy) and their various side effects due to pre-treatment have been reported. We look for the appropriate intensity of the shock wave in the electromagnetic ESWL treatment of patients with lower Inferior Ureter Stones and measure the total running time of C-arm saw. This study is based on the January-June 2014 launch of 65 patients of C university hospital located in Gyeongbuk, who conducted ESWL without pre-treatment. Patients are composed of 48 male and 17 female which were more common in men, while the most common age is 50s. The occurrence of lower urinary tract stones were left and they were more absent than 5mm in size in 39 of the most common. Optimal intensity is one of the suitable intensity of pain, and it is possible to switch the strength of impact to C if one appeals pain. In addition, the C-arm of the total operating time showed 241.73 ± 30.37 seconds, which is the size of the lower urinary tract that showed a significant difference (p <0.05). Therefore, ESWL treatment without pre-enforce treatment, the standard for the impact frequency and impact strength depending on the site of ureteral stones is required. The standard for total operating time of C-arm generated for ureteral stones is needed in order to reduce radiation exposure, and the standard for the total operating time for the criteria is needed depending on the site in order to minimize the exposure.

핵의학과 분배실 내의 공간선량률 측정

박정규(Jeong-Kyu Park),조의현(Euy-Hyun Cho) 한국디지털콘텐츠학회 2012 한국디지털콘텐츠학회논문지 Vol.13 No.2

Even though the protective facility is well made with the development of medicine, the spatial dose within the radiation section could increase the exposure of the workers. The spatial dose is always present in distribution room within the Department of Nuclear Medicine, so the spatial dose of the interior distribution room is measured and analyzed for the prediction of the exposure dose. The spatial dose rate was 6.78±0.083㎲v/h in the <SUP>18</SUP>F distribution room of department of Nuclear Medicine, 9.248±0.013 ㎲v/h in <SUP>99m</SUP>Tc, and <SUP>131</SUP>I distribution room. In addition, in case of <SUP>18</SUP>F distribution room, the yearly external exposure dose was 42.5 ㎲v when the nurse does IV in 1m in distance. It also showed that the spatial dose rate on the direction of right oblique showed higher than others by the standard of distribution window of distribution room. Therefore, the staying time of the workers should be short during distributing radiopharmaceuticals in the distribution room and the design of the distribution protection is necessary to reduce the exposure in the direction of right oblique of the protection. The utmost endeavors are required to reduce the worker’s individual exposure dose while doing IV.

심장내과의 중재적 시술시 시술조건에 따른 방사선사의 방사선 노출 특성

박정규(Jeong-Kyu Park),조의현(Euy-Hyun Cho) 한국디지털콘텐츠학회 2012 한국디지털콘텐츠학회논문지 Vol.13 No.3

Lately, the number of interventional radiology is increased by the extension of procedure in medical radiation, and radiation exposure may be appeared differently by interventional radiologists, it is caused increase of radiation dose for radiation worker, patient, and radiologists. This study has done a comparative analysis characteristic of radiation exposure for five radiologists who executed interventional cardiology for 303 patients in S university hospital of Gyeong-Buk from Nov. 1, 2011 to Jan. 31, 2011. The average exposure time of five radiologists was 697.95sec. The average of cumulative DAP(exp) for patients was 52,730mGy㎠ and the average of total DAP for patients was 104,875.14mGy㎠. The average of frames for image was 855.52 frames in acquired images, and the average of frames for images was 802.2 frames in exposure images. They were statistically significant differences (p<0.05). Exposure time, cumulative DAP(fluro), cumulative DAP(exp), total DAP, acquired image, and exposure image were high correlation except cumulative DAP(exp), and acquired runs in x-ray exposure characteristics of machine. Exposure time was a great influence on radiologist. It signified that the more exposure time lead to the more radiation dose for radiologist. Radiation dose is related to ability, experience, difficulty, and precision of procedures in interventional procedure. The number of angiography and exposure time is difficult to control by radiologists. Therefore, it is in need of reasonable system which was evaluated the real dose of medical teams in interventional proceedings. We think that self education and training are required to reduce radiation dose for radiologists and radiation workers.