구강 내 촬영용 센서의 정량적 평가

정재호,정재은,강희두,나극환,Jung, Jae-Ho,Jung, Jae-Eun,Kang, Hee-Doo,Ra, Keuk-Hwan 대한디지털의료영상학회 2009 대한디지털의료영상학회논문지 Vol.11 No.2

Carried out an experiment for quantitative evaluation about intraoral sensor among oral dental imaging equipments in PACS environment. For evaluation, testing environment & evaluation criteria are established that refer to the 'IEC 62220-1-2' and experimented with set up the standard radiation penetration that correspond with RQA-3(IEC 61267). Results of experiments using the image J, derived the ESF(edge spread function), LSF (line spread function) and calculated the MTF(modulation transfer function) finally. As a result, the MTF that 0.1, 0.2sec are 10% about 10 lp/mm and 0.32 sec is the 10% about 9 lp/mm in level represents the value of the MTF. Change of scan condition in dental environmental, according to the MTF value taken note that no changes can be seen enough. However, the dimensions of each other size $1(1200{\times}1600)$, size $2(1440{\times}1920)$ intraoral sensors for 3 lp/mm, respectively 40%, 90% of the note might have been the difference between the value of MTF, in accordance with standard sensors might note differences could be observed.

광합성균을 혼입한 시멘트 모르타르의 CO₂ 흡수성능에 관한 기초적 연구

정재호,이건철,윤승조,조재홍,최중구,Joung, Jae-Ho,Lee, Gun-Cheol,Yoon, Seung-Joe,Joe, Jae-Heung,Choi, Jung-Gu 한국건축시공학회 2015 한국건축시공학회지 Vol.15 No.1

In this research, the $CO_2$ absorption performance of mortar was investigated. The level of $CO_2$ absorption in mortar with various binders including cement and nonsintered cement was examined. As a result for the mortar with photosynthetic bacteria, the compressive strength was similar to the one without the bacteria at early age but decreased at the age of 28 days. However, for the $CO_2$ absorption, with photosynthetic, the performance of the mortar with OPC, and nonsintered cement deceased to 21%(234 ppm) and 19.7%(243 ppm) respectively after 12 hours age. 본 연구에서는 $CO_2$ 흡수형 콘크리트의 개발을 목적으로 광합성균을 혼입한 모르타르의 기초적 특성 및 $CO_2$ 흡수 성능에 대하여 검토하였다. 아울러, 결합재 종류별 $CO_2$ 흡수 가능성을 판단하기 위하여 결합재로서 시멘트 및 비소성 시멘트를 사용하여 그 특성에 대하여 검토하였다. 실험결과, 강도특성은 광합성균의 혼입한 경우 혼입 모르타르에 비해 초기강도는 유사하나 장기강도발현이 저하하는 것으로 나타났다. 그러나, $CO_2$ 농도측정 결과는 광합성균을 혼입한 경우 무혼입에 비해 12시간 후 측정치가 OPC의 경우 약 21%(234 ppm), 비소성시멘트의 경우 약 19.7%(243 ppm) 감소하는 것으로 나타났다.

단결정 압축 변형 거동의 변형구배 결정소성 유한요소해석

정재호,조경목,최윤석,Jung, Jae-Ho,Cho, Kyung-Mox,Choi, Yoon Suk 한국재료학회 2017 한국재료학회지 Vol.27 No.12

A strain-gradient crystal plasticity finite element method(SGCP-FEM) was utilized to simulate the compressive deformation behaviors of single-slip, (111)[$10{\bar{1}}$], oriented FCC single-crystal micro-pillars with two different slip-plane inclination angles, $36.3^{\circ}$ and $48.7^{\circ}$, and the simulation results were compared with those from conventional crystal plasticity finite element method(CP-FEM) simulations. For the low slip-plane inclination angle, a macroscopic diagonal shear band formed along the primary slip direction in both the CP- and SGCP-FEM simulations. However, this shear deformation was limited in the SGCP-FEM, mainly due to the increased slip resistance caused by local strain gradients, which also resulted in strain hardening in the simulated flow curves. The development of a secondly active slip system was altered in the SGCP-FEM, compared to the CP-FEM, for the low slip-plane inclination angle. The shear deformation controlled by the SGCP-FEM reduced the overall crystal rotation of the micro-pillar and limited the evolution of the primary slip system, even at 10 % compression.

안내염 및 안구로 환자에서 시행한 안구내용제거술 및 일차 보형물 삽입술 결과 비교

정재호,이종헌,전혜신,최희영,Jae Ho Jung,MD,PhD,Jong Heon Lee,MD,Hye Shin Jeon,MD,Hee Young Choi,MD,PhD 대한안과학회 2014 대한안과학회지 Vol.55 No.7

<b>Purpose:</b> To evaluate the efficacy and prognosis of evisceration with primary orbital implant placement in patients with endophthalmitis and compare it to phthisis bulbi patients. <b>Methods:</b> We retrospectively reviewed the medical records of patients who underwent evisceration with primary implant placement by a single surgeon from January 2005 to December 2011 at Pusan National University Hospital. Age, gender, underlying ocular disease, systemic illness, type and size of implant, follow-up period, and the causative organism were evaluated in patients with endophthalmitis. Success rates and prevalence of complications were compared between endophthalmitis and phthisis patients. <b>Results:</b> The present study included 18 patients (18 eyes) with endophthalmitis and 23 patients (23 eyes) with phthisis. Patients in the endophthalmitis group were older than the patients in the phthisis group and no significant differences in gender, size of implant, and underlying diseases between endophthalmitis and phthisis patients were found. Sixteen endophthalmitis and 20 phthisis patients showed successful surgical outcomes with no significant differences (<em>p </em>= 0.31), and implant exchange rates were not significantly different between endophthalmitis and phthisis bulbi patients (<em>p</em> = 0.52). <b>Conclusions:</b> Evisceration with primary orbital implant placement in patients with endophthalmitis is a safe and effective treatment method. Comparison between endophthalmitis and phthisis showed no significant differences in success outcomes and complication rates. J Korean Ophthalmol Soc 2014;55(7):958-962

의료영상 압축을 위한 JPEG2000의 효율성 연구

정재호,신진호,손기경,강희두,Jung, Jae-Ho,Shin, Jin-Ho,Son, Gi-Gyeong,Kang, Hee-Doo 대한디지털의료영상학회 2003 대한디지털영상기술학회지 Vol.6 No.1

Purpose : In a PACS(Picture Archiving Communications System) environment, which is a very important component in a digital medical environment, the compression of digital medical images is a necessary and effective feature. In a current system where JPEG is applied to the compression of medical images, this study is to examine effectiveness and suitability when the JPEG2000, a more advanced compression algorithm for still images, is applied to the compression of medical images. In this thesis, we attempt to address the compressibility for effective clinical usage when compressing medical images, applying the objectivization of clinical evaluation as a function of compressibility. In the experiment al method, the compression was applied at a fixed rate using JPEG2000, and the n the result was compared with compressed images by JPEG. Method : For the performance evaluation, we choose SNR(Signal to Noise Ratio) measurement of an objective evaluation of definition and analyze a subjective evaluation by the ROC(Receiver Operating Characteristic) method. The results of the experiment showed that in the case of JPEG2000 there is hardly any distortion of images, even at high compression ratio(100:1), while regarding noise, the SNR remains around about 40dB, which is also relatively high. Before reading by reference to evaluative materials concerning objective compressed images, it is impossible to apply high compression to images : however, after reading, this can be applied to images that have already existed for some time.

口眼와斜(特發性 顔面神經痲痺)에 關한 臨床的 考察

정재호,권강,서형식,Jung, Jae-ho,Kwon, Kang,Seo, Hyung-sik 대한한방안이비인후피부과학회 2003 한방안이비인후피부과학회지 Vol.16 No.1

Objectives : Lately the oriental medical treatment of Bell's palsy is various. In various treatments. this study reports the effect of our clinical treatment using aqua-acupuncture with hominis placenta and electroacupuncture treatment for Bell's palsy, The other purpose of this study is to compare the outcome of inpatient group with that of outpatient group. Materials and Methods : From March 1, 2003 to June 30, 2003, we observe 25 patients who visited to the department of oriental medical surgery, ophthalmology & otolaryngology, in oriental medicine hospital Sang-ji university with Bell's palsy. limited to patients who receive treatment more than 5th times and 4 weeks poured aqua-acupunture with homonis placenta both inpatient group and outpatient group, Inpatient group used electroacupunture treatment after 1 week after onset and outpatient group used electroacupunture treatment after 4 weeks after onset. Results and Conclusions : 40$\%$ were male and 60$\%$ female. Of 25 cases. 30's and 50's were 24$\%$ respectively, 40's, 60's and over 70 were 16$\%$ respectively, 20's were 4$\%$. 50$\%$ of male and 60$\%$ of female had the affected side at left side and right occured at 50$\%$ of male and 40$\%$ of female. The most common cause of Bell's palsy was nonspecific 36$\%$, followed by labor 28$\%$, stress 20$\%$, In 48$\%$ of all cases, 2~3 days were spent before a patient visited the hospital after onset, followed by 4~7 days (24$\%$), 44$\%$ were treated 11~20 times followed by those who received 21~30 times (28$\%$). The results of treatment with aqua-acupunture wth hominis placenta and electroacupunture treatment showed that 21 of 25(84$\%$) patients achived fair or more recovery. the overall therapeutic rate of inpatient group was 90.9$\%$, which was higher than that of outpatient group(78.6$\%$).

Inherited Metabolic Disorders Involving the Eye

정재호,Jae Ho, Jung The Korea Society of Inherited Metabolic Disease 2022 대한유전성대사질환학회지 Vol.22 No.2

Inherited metabolic disorders (IMD) are a large group of rare disorders affecting normal biochemical pathways. The ophthalmic involvement can be very varied affecting any part of the eye, including abnormalities of cornea, lens dislocation and cataracts, retina and the optic nerve, and extraocular muscles. Eye disorders can be initial symptoms of some IMD and can be clue for diagnosis of IMD. However, eye disorders can evolve later in the natural history of an already diagnosed metabolic disorder. Awareness of IMDs is important to facilitate early diagnosis and in some cases instigate early treatment if a patient presents with eye involvement suggestive of a metabolic disorder. Ophthalmological interventions are also an important component of the multisystem holistic approach to treating patients with metabolic disorders.

증식당뇨망막병증에서 유리체절제술 후 불량한 시력을 보이는 인자

정재호,엄부섭,Jae-Ho Jung,Boo-Sup Oum 대한안과학회 2005 대한안과학회지 Vol.46 No.3

Purpose: To evaluate the predisposing factors of a visual acuity of less than 0.1 after vitrectomy in proliferative diabetic retinopathy. Methods: The medical records of 310 eyes of 295 patients were reviewed, and the eyes were divided into 2 groups : postoperative visual acuity less than 0.1 (131 eyes, 42.2%), and more than 0.1 (179 eyes, 57.8%). Results: Univariate analysis revealed that postoperative visual acuity of less than 0.1 was associated with preoperative retinal detachment, preoperative macular detachment, intraocular tamponade, absence of cataract operation, preoperative visual acuity of less than 0.02, and a treatment need for postoperative high intraocular pressure. Multivariate analysis revealed that postoperative visual acuity of less than 0.1 was associated with preoperative macular detachment and treatment for high postoperative intraocular pressure. Conclusions: This study showed that diabetic patients who have visual acuity less than 0.1 after vitrectomy are likely to have preoperative macular detachment or to need treatment for postoperative high intraocular pressure.

PACS환경에서 디지털유방엑스선 영상 화질에 관한 연구

정재호,Jung, Jae-Ho 대한디지털의료영상학회 2014 대한디지털의료영상학회논문지 Vol.16 No.2

The full-field digital mammography (FFDM), which has been known as a digital breast imaging system, carries out more outstanding performance than the screen-film mammography in overall image quality, skin & nipple, description of pectoral muscle and expression of micro-calcification. Thus, in this thesis, I perform experiments for both the enhancement of image quality and accurate estimation of the result in question, when detecting the very tiny-sized lesions in mammography. The image of digital breast X-rays is the important diagnostic tool for detecting early breast cancer and micro calcification lesion. The experiment of how much compression rate has an effect on the result of diagnosis in the case of microcalcification lesion, with JPEG2000 40:1 compression and over 50% enlargement led to obscure or definitely unacceptable diagnostic results is performed. And in another study of assessment of PSNR degree. I recognized the importance of standardized management system in mammography, where not to mention the accurate reading of the image has the most crucial role in diagnosis

면내 선형분포하중을 받는 수평보강재가 설치된 직교이방성판의 좌굴강도

정재호,윤순종,조선규,Jung, Jae Ho,Yoon, Soon Jong,Cho, Sun Kyu 한국강구조학회 1998 韓國鋼構造學會 論文集 Vol.10 No.3

본 연구는 수평보강된 직교이방성판의 좌굴거동에 관한 것으로서 면내 선형분포하중을 받는 수평보강된 직교이방성판의 좌굴해석식을 Rayleigh-Ritz법을 사용하여 유도하였으며 보강재의 위치에 따른 좌굴응력의 상한치를 Lagrangian multiplier법을 사용하여 결정하였다. 판의 네 변은 단순지지되어 있다고 가정하였으며, 보강재는 보요소로 간주하였다. 유도된 식을 사용하여 보강재와 판의 폭비와 보강재의 위치를 변화시켜가며 좌굴해석을 수행한 결과 면내 선형분포하중을 받는 네 변이 단순지지된 수평보강된 직교이방성판의 효과적인 보강재의 설치 위치는 판의 좌굴응력의 상한치가 최대가 되는 위치임을 알 수 있었다. In this study buckling behavior of orthotropic plate with a longitudinal stiffener under in-plane linearly distributed loads is investigated. All edges of plate are assumed to be simply supported and the stiffener is considered as a beam element. For the equation of buckling analysis Rayleigh-Ritz method is employed. The upper limit of the critical stress at various location of stiffener is determined by using Lagrangian multiplier method. Buckling analysis is performed for the various position of stiffener and for the various width ratios between plate and stiffener. The parametric study shows that, when four edges of plate are simply supported, the most effective position for a longitudinal stiffener is at the location of which the upper limit of the stress is the maximum.