드론을 활용하고 음성 FFT분석에 기반을 둔 컨베이어 시스템의 원격 고장 검출

염동주,이보희 중소기업융합학회 2019 융합정보논문지 Vol.9 No.10

본 논문은 화력 발전소 및 시멘트 산업에서 필요한 원자재의 운송 수단에 사용되는 컨베이어 시스템에서의 고장을 검출하는 방법을 제안하였다. 산업현장에서 사람이 접근하기가 힘들고 넓은 공간에 시스템이 동작 하는 점을 고려하여 소 형 드론을 설계하였고 컨베이어의 이상을 감지하기 위하여 컨베이어에 내장된 모터의 이상 소음을 감지하는 방법을 임베디 드 환경으로 설계하여 드론에 장착하는 구조로 제안하였다. 시스템을 임베디드 마이크로프로세서에 적용하기 위하여 제한 된 메모리와 수행 시간을 고려한 하드웨어 및 알고리즘을 제안하였으며 주파수 분석을 통해 고장의 경향을 파악하여 알고 리즘 화 하였다. 이때 고장 판별 방식은 측정을 통하여 피크주파수를 측정하고 고주파수의 연속성을 감지하는 방식으로 고장에 의한 소음의 높은 주파수를 분석하여 고장진단을 시행할 수 있었다. 제안된 시스템은 실제 화력 발전소에서 취득한 데이터를 바탕으로 실험 환경을 구성하였으며 드론에 설계된 시스템을 탑재하여 가상 환경 실험을 하여 제안된 시스템의 유용성을 확인하였다. 향후에는 드론의 비행 안정성 향상과 고장 주파수에 대한 좀 더 정밀한 방법을 사용하여 판별성능을 향상 시키는 연구가 요구된다. This paper proposes a method for detecting faults in conveyor systems used for transportation of raw materials needed in the thermal power plant and cement industries. A small drone was designed in consideration of the difficulty in accessing the industrial site and the need to use it in wide industrial site. In order to apply the system to the embedded microprocessor, hardware and algorithms considering limited memory and execution time have been proposed. At this time, the failure determination method measures the peak frequency through the measurement, detects the continuity of the high frequency, and performs the failure diagnosis with the high frequency components of noise. The proposed system consists of experimental environment based on the data obtained from the actual thermal power plant, and it is confirmed that the proposed system is useful by conducting virtual environment experiments with the drone designed system. In the future, further research is needed to improve the drone's flight stability and to improve discrimination performance by using more intelligent methods of fault frequency.

전방각이 얕은 환자에게 시행한 레이저홍채절개술 전후의 전방각 계측치의 변화

염동주,이주화,Dong Ju Yeom,Joo Hwa Lee 대한안과학회 2010 대한안과학회지 Vol.51 No.11

Purpose: To identify the impact of the presence of peripheral anterior synechia (PAS) on the depth of the anterior segment in patients with a shallow anterior chamber after laser iridotomy (LI) by analyzing changes in the anterior segment biometry using ultrasound biomicroscopy (UBM). Methods: Twenty eyes of 20 patients with PAS and shallow anterior chamber, and another 20 eyes of 20 patients with shallow anterior chamber without PAS were studied. The changes in the anterior segment biometry for each group of patients were examined using gonioscopy and UBM before and after the LI. Results: The central corneal thicknesses and scleral thicknesses of the two groups did not show significant differences (p > 0.05). The anterior chamber depths, anterior chamber angles, trabecular meshwork-iris distances, and angle-opening distances 500 increased significantly after the peripheral LI (p < 0.05) in both groups. However, the difference in the increases in the anterior segment biometries between the two groups was not statistically significant. Conclusions: LI can increase the depth of the anterior chamber regardless of the presence of PAS. J Korean Ophthalmol Soc 2010;51(11):1479-1484

건강 검진을 위해 내원한 50세 이상 한국 성인에서 유리체망막 질환의 유병률

염동주,오현섭,유형곤,송수정 대한안과학회 2009 대한안과학회지 Vol.50 No.11

Purpose: To describe the prevalence of vitreoretinal diseases in the Korean population 50 years or older at a health screening center. Methods: The participants of this study included 11,180 adults 50 years of age and older who visited the Health Promotion Center of Kangbuk Samsung Hospital from January to December 2006. Digital images of non-mydriatic fundus photographs were examined. We calculated the sex- and age-adjusted prevalence of vitreoretinal diseases using the direct standardized method based on the number of resident registrations. Results: The age- and sex-adjusted prevalence of vitreoretinal diseases in Korean adults 50 years of age and older was 9.9%. The prevalence of vitreoretinal diseases significantly increased with age (P=0.000). There was no significant gender difference in the prevalence of vitreoretinal diseases (p=0.553). Age-related macular degeneration was the most common vitreoretinal disease, with an age- and sex-adjusted prevalence of 5.2%. Epiretinal membrane, retinal vein occlusion, and diabetic retinopathy were common vitreoretinal diseases in that order, and the age- and sex-adjusted prevalences were 1.5%, 1.1%, and 0.9%, respectively. Conclusions: The prevalence of vitreoretinal diseases in a screened Korean population 50 years and older was 9.9%. Vitreoretinal diseases are a major ophthalmic problem in Korea. As the Korean population continues to age and the prevalence of diabetes increases, further investigations about the epidemiology and prevention of vitreoretinal diseases are needed. 목적: 건강 검진을 위해 내원한 50세 이상의 한국 성인에서 유리체망막 질환의 유병률을 알아보고자 하였다. 대상과 방법: 2006년 1월부터 2006년 12월까지 강북삼성병원 종합검진센터에서 건강 검진을 받은 50세 이상의 성인 11,180명의 안저 사진을 대상으로 하였다. 유리체망막 질환의 유병률을 2005년 주민등록인구를 기준으로 직접표준화법으로 연령 및 성별을 보정하여 산출하였다. 결과: 유리체망막 질환의 연령 성별 보정 후 유병률은 9.9%였다. 유리체망막 질환의 유병률은 유의하게 나이가 많을수록 증가하였으나 (p=0.000), 성별에 따른 차이는 없었다(p=0.553). 가장 흔한 유리체망막 질환은 나이관련황반변성으로 연령 성별 보정 후 유병률은 5.2% 였다. 다음으로 흔한 질환은 망막앞막, 망막정맥폐쇄, 당뇨망막병증 순이었으며, 각각의 유병률은 1.5%, 1.1%, 0.9%였다. 결론: 유리체망막 질환의 유병률은 9.9%로 유리체망막 질환은 한국에서 주요 안 질환 중 하나로 생각된다. 한국의 고령사회 진입 속도와 당뇨병 유병률의 증가 속도를 생각할 때 유리체망막 질환의 역학과 예방에 대한 연구가 중요할 것으로 생각된다.

네트웍 기반 모듈라 로봇의 원격 제어

염동주,이보희 중소기업융합학회 2018 융합정보논문지 Vol.8 No.5

동작을 기억하는 모듈라 로봇은 손으로 직접 표현하기 때문에 창의적 구조물을 쉽게 만들고, 동작시킬 수 있다. 하지만 사용자에 의하여 만들어진 동작을 저장할 충분한 저장 공간이 모듈 내에 없어서 만들어진 동작을 재사용이 불가능하며 모듈라 로봇이 다시 동작을 기억할 시에 다른 동작으로 바뀌게 된다. 또한, 다수의 모듈라 로봇을 동시에 동작시킬 수 있는 주 제어기가 없어서 직접적으로 사용자가 모듈라 로봇에 입력해야하는 단점이 있다. 이러한 단점을 극복하고자, 유선 및 무선 네트웍을 이용하고 웹 서버 및 컴퍼넌트 기반 소프트웨어를 설계하여, 주변의 스마트 기기에서 동작시킬 수 있는 원격제어기를 제안하였다. 그리고 제안된 제어기의 하드웨어 개념 및 소프트웨어의 연결 관계를 자세히 제시 하였다. 제안된 방식은 모듈라 로봇에 연결하여 다양한 형태의 구조물을 만들어 동작시키고 저장한 후 다시 재생 동작을 수행하여 동작의 재현성을 보였으며 기존의 저장된 동작을 효과적으로 재생함으로써 유용성을 확인하였다. 아울러 다운로드한 궤적 데이터를 도해적으로 표현하고 실제 동작된 궤적과의 차이를 분석하여 신뢰성을 확인하였다. 향후에는 원격제어기에 저장된 궤적을 인공지능 기법을 이용하여 표준화시켜 모듈라 로봇의 동작을 손쉽게 구현 시킬 예정이다. A modular robot that memorizes motion can be easily created and operated because it expresses by hand. However, since there is not enough storage space in the module to store the user-created operation, it is impossible to reuse the created operation, and when the modular robot again memorizes the operation, it changes to another operation. There is no main controller capable of operating a plurality of modular robots at the same time, and thus there is a disadvantage that the user must input directly to the modular robot. To overcome these disadvantages, a remote controller has been proposed that can be operated in the surrounding smart devices by designing web server and component based software using wired and wireless network. In the proposed method, various types of structures are created by connecting to a modular robot, and the reconstructed operation is performed again after storing, and the usefulness is confirmed by regenerating the stored operation effectively. In addition, the reliability of the downloaded trajectory data is verified by analyzing the difference between the trajectory data and the actual trajectory. In the future, the trajectory stored in the remote controller will be standardized using the artificial intelligence technique, so that the operation of the modular robot will be easily implemented.

The Effect of Various Factors on Variability of Retinal Nerve Fiber Layer Thickness Measurements Using Optical Coherence Tomography

염동주,김현중,심성희,장효주,김준모,박기호,최철영,조정곤 대한안과학회 2012 Korean Journal of Ophthalmology Vol.26 No.2

Purpose: To evaluate the effects of various factors on the variability of retinal nerve fiber layer (RNFL) thickness measurements using the Stratus optical coherence tomography (OCT) in normal and glaucomatous eyes. Methods: Four hundred seventy-four subjects (103 normal eyes and 371 glaucomatous eyes) were scanned to determine the RNFL thickness measurements using the Stratus OCT. Measurements were obtained twice during the same day. The standard deviation (SD) was used to compare the variability in RNFL thickness measurements of the normal subjects to that of the glaucomatous patients. Multivariate regression analysis was used to evaluate which covariates were independent predictors of SD in overall mean RNFL thickness. Results: The mean SD of all RNFL thickness measurements was larger in the glaucoma group except in one sector. In the multivariate regression analysis, the average signal strength (SS) and the relative SS change (difference in SS between initial and repeat scans, divided by initial SS) were independent predictors of the SD in the RNFL thickness measurements (partial R2 = 0.018, 0.013; p = 0.016, 0.040, respectively). Conclusions: Glaucomatous eyes tend to be more variable than normal eyes in RNFL thickness measurement using the Straus OCT. The average SS and the relative SS changes appear to correlate with the variability in RNFL thickness measurement. Therefore, the results of the RNFL analysis should not be interpreted independently of these factors.

에폭시 수지가 적용된 유리섬유 복합재료의 극저온 환경 기계적 특성 분석을 통한 LNG CCS 적용성 평가

염동주(Dong-Ju Yeom),방승길(Seoung-Gil Bang),정연제(Yeon-Jae Jeong),김희태(Hee-Tae Kim),박성보(Seong-Bo Park),김용태(Yong-Tai Kim),오훈규(Hoon-Gyu Oh),이제명(Jae-Myung Lee) 대한조선학회 2021 大韓造船學會 論文集 Vol.58 No.4

조절내사시 환아의 장기적 양안시성

염동주(Dong Ju Youm),장혜란(Hae Ran Chang) 대한안과학회 2015 대한안과학회지 Vol.56 No.5

목적: 조절내사시 환아에서 장기적인 양안시성과 관련된 요소들을 알아보고자 하였다. 대상과 방법: 안경교정(이중초점안경 포함)만으로 근거리와 원거리 사시각이 8 프리즘디옵터 이하로 조절되고, 5년 이상 추적관찰이 가능했던 조절내사시 환아 49명을 대상으로 하였다. 최종 입체시가 50초각 또는 그보다 좋고 중심융합이 있으며 망막중심오목억제가 없는 환아를 두눈망막중심오목용합군, 그 외의 경우를 주변융합군으로 분류하고 두 군의 임상 요소를 비교 분석하였다. 결과: 두눈망막중심오목용합군 15명, 주변융합군 34명이었고, 추적관찰 기간은 평균 88.9 ± 25.4개월이었다. 두눈망막중심오목용합군은 주변융합군에 비해 발병 연령이 높고(p<0.01), 사시에 노출된 기간이 짧았으며(p<0.01), 초진 시(p<0.01) 및 첫 안경교정 후(p <0.02) 간헐사시가 많았고, 첫 안경교정 후(p<0.01) 및 최종 진료 시(p<0.01) 원거리 사시각이 작았고, 약시가 적었다(p<0.01). 결론: 장기적으로 우수한 양안시를 얻기 위해서는 조절내사시가 간헐적이고, 약시가 발생하기 전에 적절한 안경교정을 해 주어야 하며, 안경교정 후 작은 사시각을 유지하는 것이 중요할 것으로 생각된다. <대한안과학회지 2015;56(5):759-763> Purpose: To find clinical factors related to the long-term outcome of binocularity in accommodative esotropia. Methods: Forty-nine patients with accommodative esotropia who were followed over 5 years after successful optical alignment within 8 prism diopters of orthophoria at near and distance with glasses including bifocals were included. The patients who had stereo acuity better than 50 seconds/arc and central fusion without suppression scotoma at the final visit were divided into the bi-foveal fusion group and the others were divided into the peripheral fusion group. Clinical factors were analyzed between the two groups (Chi-square test, student t-test). Results: Of the 49 patients, 15 patients were included in the bifoveal fusion group and 34 patients were included in peripheral fu-sion group. Mean follow-up was 88.9 ± 25.4 months. Clinical factors that were significantly related to the bifoveal fusion group were older age of onset, shorter duration of misalignment, intermittent esotropia at the initial visit and after initial optical correc-tion, smaller residual deviations at distance after initial optical correction and at the final visit, and lesser amblyopia. Conclusions: To obtain better levels of long-term binocularity, optical correction should be done as early as possible, before the presence of constant eye misalignment or amblyopia, and the residual esodeviations after optical correction should be kept as small as possible. J Korean Ophthalmol Soc 2015;56(5):759-763

순수소안구증에 동반된 급성폐쇄각녹내장 1예

황제형,염동주,김재석,이주화,Je Hyung Hwang,MD,Dong Ju Yeom,MD,Jae Suk Kim,MD,Joo Hwa Lee,MD 대한안과학회 2010 대한안과학회지 Vol.51 No.2

Purpose: To present a case of acute angle-closure glaucoma in a nanophthalmos patient. Case summary: A 28-year-old woman visited the hospital for a sudden pain in the left eye, she had a small orbital bone and narrow palpebral fissurea in both eyes. Her intraocular pressure (IOP) was 58 mmHg in the left eye. The slit lamp examination showed shallow anterior chambers in both eyes, and the gonioscopic examination showed a closed angle in the left eye. The diameters of the corneas were 11 mm , and the axial lengths were 19.7 mm in the right eye and 19.6 mm in the left eye. The depths of the anterior chambers were 1.51 mm in the right eye and 1.82 mm in the left eye. The disease was diagnosed as acute angle-closure glaucoma in the left eye of the patient with nanophthalmos, and thus the IOP of the left eye was lowered using ophthalmic drugs and medications. Laser iridotomy was performed on both eyes. Conclusions: For around a year of follow-up after laser iridotomy, complications such as the rise of intraocular pressure and choroidal effusion were not observed. This suggests that laser iridotomy can be an effective treatment for acute angle-closure glaucoma accompanying nanophthalmos. J Korean Ophthalmol Soc 2010;51(2):303-306

접형동, 사골동의 비강형 자연살해/T 세포 림프종에 의한 안와첨증후군 1예

백승화,염동주,강윤경,성미선,문상웅,Seung Hwa Baik,Dong Ju Yeom,Yun Kyung Kang,Mi Sun Sung,Sang Woong Moon 대한안과학회 2010 대한안과학회지 Vol.51 No.2

Purpose: To report a case of nasal-type NK/T cell lymphoma occurring in the sphenoid and ethmoid sinuses of an orbital apex syndrome patient. Case summary: A 61-year-old male patient visited our hospital for the impairment of vision in the right eye for the previous month, and for right-side blepharoptosis, pain around the eyeball, and limitation of extraocular movement in the right eye for three days earlier. In MRI (magnetic resonance image) and CT (computed tomography), shades with vague boundaries were observed in the right sphenoid and ethmoid sinuses, and open biopsy and decompression were performed for the lesions. After the surgery, the vision of the right eye increased, and improvement was observed in the right blepharoptosis, the pain around the eyeball, and in the limitation of motility of the extraocular muscle in the right eye. The patient was diagnosed with nasal type NK/T cell lymphoma in biopsy, and radiotherapy and chemotherapy were performed. J Korean Ophthalmol Soc 2010;51(2):286-291

LNG 화물창 2차 방벽의 기계적 성능에 아라미드 섬유가 미치는 영향에 대한 연구

방승길(Seoung-Gil Bang),염동주(Dong-Ju Yeom),정연제(Yeon-Jae Jeong),김희태(Hee-Tae Kim),김정대(Jeong-Dae Kim),이제명(Jae-Myung Lee) 대한조선학회 2021 大韓造船學會 論文集 Vol.58 No.4