2차원 위상비교 방향탐지를 위한 수신기 설계 및 제작

전종화,조성진,채명호,Jeon, Jonghwa,Jo, Sungjin,Chae, Myoungho 한국군사과학기술학회 2020 한국군사과학기술학회지 Vol.23 No.1

In this paper, a 2-dimensional phase comparison direction finding receiver was designed and fabricated. For 2-D comparison direction finding, direction finding formulas were derived from a uniformly arranged of four antennas. Based on this, a direction finding receiver was designed using Matlab simulink, and the direction finding receiver was fabricated. To analyze the performance of the designed direction finding receiver, the injection direction finding accuracy and simulation results were compared. As a result of the test, the fabricated direction finding receiver showed a maximum of 3° RMS precision, and the result of both tests showed similar trends. Also, it was confirmed that the direction finding accuracy of elevation angle is about 2.7 times better than azimuth angle, and both models performed well within 0.7° RMS at the boresight.

Simultaneous Triple Microbial Keratitis

전종화 대한안과학회 2019 Korean Journal of Ophthalmology Vol.33 No.6

Development of GNSS-only On The Move-RTK Technique for Highly Maneuvering Ground Vehicles

전종화,유상훈,최정원,성태경 사단법인 항법시스템학회 2018 Journal of Positioning, Navigation, and Timing Vol.7 No.4

Conventional Real Time Kinematics (RTK) collect measurements in stationary state for several minutes to resolve the integer ambiguity in the carrier phase measurement or resolve the integer ambiguity on the move assuming low maneuvering movement. In this paper, an On The Move-RTK (OTM-RTK) technique that resolves the integer ambiguity on the move for fast and precise positioning of ground vehicles such as high maneuvering vehicles was proposed. The OTM-RTK estimates the precise amount of movement between epochs using the carrier phase measurements acquired on the move, and by using this, resolves the integer ambiguity within a short period of time by evaluating the integer ambiguity candidates for each epoch. This study analyzed the integer ambiguity resolution performance using field driving experiment data in order to verify the performance of the proposed method. The results of the experiment showed that the precise trajectory including the initial position bias can be obtained prior to resolving the integer ambiguity, and after resolving the integer ambiguity on the move, it was possible to obtain the bias-corrected precise position solution. It was confirmed that the integer ambiguity can be resolved by collecting measurements of about 10 epochs from the moving vehicle using a dual frequency receiver.

반복된 단순포진 각막염의 반흔에 발생한 포마 그로메라타 진균각막염 1예

전종화,류남희,장성동 대한안과학회 2014 대한안과학회지 Vol.55 No.8

Purpose: To report a case of Phoma glomerata keratitis occurring in recurrent herpes simplex keratitis cicatrix. Case summary: A 63-year-old male patient was admitted to our hospital with complaints of abrupt visual deterioration and ocular pain in his left eye. He was treated for recurrent herpes simplex keratitis in the same eye 12 years prior. Because central desmatocele was observed as a result of advanced corneal stromal melting, Gram staining, Potassium Hydroxide (KOH) mount, and culture were performed in corneal scrape specimens. On microbiological evaluation, a Phoma species was detected and Phoma glomerata was diagnosed using DNA sequencing method. Two consecutive amniotic membrane transplantations were performed with topical antifungal agents. The lesion was not improved when using topical amphotericin B and natamycin eyedrops, thus fluconazole eyedrops were used additionally. The corneal infection was resolved with central thick opacification. Conclusions: In the present case, herpetic keratitis was the main underlying causative factor because the patient had no past history of trauma. When diverse appearances of keratitis occur in herpes simplex keratitis patients, clinicians need to consider the concurrence of fungal infection, especially Phoma glomerata, a rare fungal organism. J Korean Ophthalmol Soc 2014;55(8):1229-1232

초심자 안과 전문의 10명에 의해 시행된 수정체유화술 중 발생한 후낭파열의 임상양상

전종화,장성동,Jong Hwa Jun,MD,Sung Dong Chang,MD,PhD 대한안과학회 2014 대한안과학회지 Vol.55 No.5

Purpose: To report the related factors of posterior capsule rupture and the difference of postoperative visual prognosis after phacoemulsification by analyzing clinical features of the surgery performed by ten novice ophthalmologists. Methods: We retrospectively evaluated electronic medical records of 326 patients (412 phacoemulsification cases) who underwent surgery by novice ophthalmologists certified by the Board of Ophthalmology after a resident training program. Results: The number of cataract surgeries performed by each surgeon within the ophthalmology fellowship period (6 months - 2 years) ranged from 16 to 75 eyes, and perioperative posterior capsule ruptures occurred in 64 of 412 eyes (15.5%). Factors such as age, sex, laterality, axial length and clinical courses were not related to the rate of posterior capsule rupture. Nucleosclerosis was significantly related to the posterior capsule rupture rate and was especially higher in the group with a grade higher than five compared to that in the groups with a grade less than 5 based on the Lens Opacities Classification System III (<em>p</em> = 0.033). Factors of surgeon's subspecialty, nucleofractis method, and period between residency and the fellowship were not related to the posterior capsule rupture rate, except when considering anesthetic methods. The posterior capsule rupture rate was less frequent in the retrobulbar surgery group than the topical surgery group (<em>p</em> = 0.046). Postoperative visual outcomes were significantly different at postoperative day one and one month (<em>p</em> = 0.023, 0.022, respectively) but not at postoperative two months (<em>p</em> = 0.059). Conclusions: Phacoemulsifications performed by novice ophthalmologists showed a statistically significant difference in posterior capsule rupture rate between nucleosclerosis and anesthesia groups. Postoperative visual outcome differed at postoperative day one and one month but not after two months postoperatively. J Korean Ophthalmol Soc 2014;55(5):679-685

L대역 신호 수집을 위한 소형 디지털 수신기 설계 및 제작

전종화,조성진,채명호 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.11

In this paper, we have designed and fabricated a compact digital receiver for acquiring L-band signals. A receiver, based on direct RF sampling, has been designed for a compact multi-channel receiver. The design of the receiver is based on the system parameters and it is further fabricated on the basis of the simulation model. The performance of the fabricated digital receiver is analyzed by comparing it with the performance of the simulation model. It is observed that the fabricated digital receiver exhibits a receive sensitivity of −102 dBm, and eventually reaches the dynamic range of 62.7 dB.

유전자염기서열 분석에 의해 확진된 뷰베리아 바시아나 각막염

전종화,류남희,김의종,장성동,Jong Hwa Jun,Nam Hee Ryoo,Eui Chong Kim,Sung Dong Chang 대한안과학회 2014 대한안과학회지 Vol.55 No.6

Purpose: To report a case of Beauveria bassiana keratitis that was confirmed by gene sequencing. Case summary: A 70-year-old man presented to our hospital with complaints of ocular pain and deterioration of the visual acuity in his left eye after injury caused by a wood branch one week previously. Visual acuity in the left eye was 20/400 at the time of the first visit. Slit lamp examination showed a central 0.7 × 2.5-mm-sized epithelial defect surrounded by cellular infiltration in the stroma. Scraping of the corneal lesion for microbiological examinations was performed. Initial Gram stain, potassium hydroxide (KOH) mount, and culture were negative. However, fungal hyphae were observed on a KOH mount of the repeated corneal scraping specimen, and a Beauveria species was suspected based on the culture. Beauveria bassiana was confirmed using a MicroSEQ<sup>® D2 large-subunit ribosomal DNA fungal sequencing kit. Natamycin eye solution was initially instilled bihourly (every two hours), but the persistent epithelial defect and progressive stromal melting finally resulted in a descemetocele. Temporary and permanent amniotic membrane transplantations were performed, and amphotericin B eye solution was administered bihourly (every two hours). The ulcerous lesion gradually improved with no evidence of recurrence. Conclusions: Recently, cases of fungal keratitis have been increasing. Therefore, molecular diagnosis methods such as gene sequencing can be helpful in diagnosis and in improving the prognosis of fungal keratitis caused by rare fungi, as we found in this case. J Korean Ophthalmol Soc 2014;55(6):923-927

굴절조절내사시에서 원시정도에 따른 임상양상

전종화,이영춘,이세엽,Jong-Hwa Jun,Young-Chun Lee,Se-Youp Lee 대한안과학회 2008 대한안과학회지 Vol.49 No.4

Purpose: This study examined differences in clinical patterns according to the hyperopia level in refractive-accommodative esotropia patients. Methods: Ninety-four refractive-accommodative esotropia patients were divided into 3 groups according to hyperopia level: group 1, ≥ +1.00D and < +3.00D group 2, ≥ +3.00D and < +5.00D and group 3, ≥ +5.00D. The following factors were analyzed retrospectively: the initial corrective visual acuity, the final corrective visual acuity, the angle of esotropia with or without hyperopic correction, the recovery time to orthophoria after hyperopic correction, the change in hyperopia level, and the frequency of amblyopia. Results: The angles of esotropia without hyperopic correction in groups 1, 2 and 3 were 18.4±7.3PD, 22.9±8.5PD, and 25.7±10.4PD, respectively. The angle of esotropia was found to be significantly greater in the group with the higher level of hyperopia (p=0.01). The monthly change in hyperopia in groups 1, 2 and 3 was 0.018±0.02D, 0.028±0.03D and 0.043±0.03D. The change was greater in the group with the higher level of hyperopia (p=0.009). Conclusions: In refractive-accommodative esotropia patients, the more the hyperopia without correction increases, the more the angle of esotropia without correction increases, and the larger the reduction of hyperopia after correction becomes.

Development of 3-Dimensional Position/Attitude Determination Radio-navigation System with FLAOA and TOA Measurements

전종화,임종민,유상훈,성태경 사단법인 항법시스템학회 2018 Journal of Positioning, Navigation, and Timing Vol.7 No.2

Existing radio positioning systems have a drawback that the attitude of user's tag is difficult to be determined. Although forward link angle of arrival (FLAOA) technology that uses measurements of array antenna arranged in a tag among the angle of arrival (AOA) technologies can estimate attitude and positioning of tags, it cannot extend the estimated results into threedimensional (3D) results due to complex non-linear model displayed because of the effects of 3D positioning and attitude in tags. This paper proposed a radio navigation technique that determines 3D attitude and positioning via FLAOA / time of arrival (TOA) integration. According to the order of determining attitude and positioning, two integration techniques were proposed. To analyze the performance of the proposed technique, MATLAB-based simulations were used to verify the performance. The simulation results showed that the first proposed method, TOA-FLAOA integrated technique, showed about 0.15 m of positioning error, and 2–3° of attitude error performances regardless of the positioning space size whereas the second method, differenced FLAOA-TOA integrated technique, revealed a problem that a positioning error became larger as the size of the positioning space became larger.

Design and Fabrication of a Compact 2D Phase Comparison Direction Finder

전종화,채명호 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.3

In this study, a compact, low-power 2D phase comparison direction finder was designed and fabricated. For the design of the directionfinding (DF) receiver, a 2D phase comparison DF equation was derived from the structure of four uniformly arranged antennas, and the main design parameters were derived from the receiver’s system parameters. Based on the derived DF equations and design parameters, a DF receiver was designed, and a direction finder was fabricated. A comparison of the fabricated direction finder to a simulation model showed that its performance was comparable to the simulated performance and satisfied the system parameters. Moreover, a comparison of the theoretical, simulated, and actual injection and radiation DF precision showed that the fabricated direction finder had performance consistent with that indicated by the theoretical and simulation results and DF precision within 0.5°.