A New Application of Human Visual Simulated Images in Optometry Services

Lin-Song Chang,Bo-Wen Wu 한국광학회 2013 Current Optics and Photonics Vol.17 No.4

Due to the rapid advancement of auto-refractor technology, most optometry shops provide refraction services. Despite their speed and convenience, the measurement values provided by auto-refractors include a significant degree of error due to psychological and physical factors. Therefore, there is a need for repetitive testing to obtain a smaller mean error value. However, even repetitive testing itself might not be sufficient to ensure accurate measurements. Therefore, research on a method of measurement that can complement auto-refractor measurements and provide confirmation of refraction results needs to be conducted. The customized optometry model described herein can satisfy the above requirements. With existing technologies, using human eye measurement devices to obtain relevant individual optical feature parameters is no longer difficult, and these parameters allow us to construct an optometry model for individual eyeballs. They also allow us to compute visual images produced from the optometry model using the CODE V macro programming language before recognizing the diffraction effects visual images with the neural network algorithm to obtain the accurate refractive diopter. This study attempts to combine the optometry model with the back-propagation neural network and achieve a double check recognition effect by complementing the auto-refractor. Results show that the accuracy achieved was above 98% and that this application could significantly enhance the service quality of refraction.

Influence of different parameters on nonlinear friction-induced vibration characteristics of water lubricated stern bearings

Lin Chang-Gang,Zou Ming-Song,Zhang Hai-Cheng,Qi Li-Bo,Liu Shu-Xiao 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

To investigate the mechanism of friction-induced vibration and noise of ship water lubricated stern bearings, a two-degree-of-freedom (2-DOF) nonlinear self-excited vibration model is established. The novelty of this work lies in the detailed analysis of influence of different parameters on the stability and nonlinear vibration characteristics of the system, which provides a theoretical basis for the various friction vibration and noise phenomenon and has a very important directive meaning for low noise design of water lubricated stern bearings. The results reveal that the change of any parameter, such as rotating speed of shaft, contact pressure, friction coefficient, system damping and stiffness, has an important influence on the stability and nonlinear response of the system. The vibration amplitudes of the system increase as (a) rotating speed of shaft, contact pressure, and the ratio of static friction coefficient to dynamic friction coefficient increase and (b) the transmission damping between motor and shaft decreases. The frequency spectrum of the system is modulated by the first mode natural frequency, which is continuous multi-harmonics of the first mode natural frequency. The response of the system presents a quasi-periodic motion.

A Study on Shape and Height of Shipwaves

Song-lin Gang,Mi-Kum Kim,Chang-Je Kim 한국항해항만학회 2009 한국항해항만학회지 Vol.33 No.2

Shipwaves can have harmful effects on ships working on the sea. in a harbour or navigational channel and caused beach erosion, seawall destruction. This study aims to investigate describe the characteristics of the wave pattern generated by an individual model ship tested at different velocities and hull forms for a given water depth and to investigate the variations at a given distance from the sailing line under the same conditions. As a result, the angles a's by model ship tests are smaller than those by real ship ones. Wave heights decreases with an increasing the mid-ship cross sectional area As. The maximum wave height and period increase rapidly in the sabcritical speed, and beyond the critical speed the height and period decrease with increasing depth Froude number. And the period keeps constant with the distance from the sailing line.

Clinical and radiologic preoperative predicting factors for GB cholesterol polyp

Hye-Lin Song,Jun-Ho Shin,Hungdai Kim,Yong-Lai Park,Chang-Hak Yoo,Byung-Ho Son,Ji-Sup Yoon,Hyung-Ook Kim 대한외과학회 2012 Annals of Surgical Treatment and Research(ASRT) Vol.82 No.4

Purpose: To use the clinical and radiological data to differentiate non-cholesterol versus cholesterol gall bladder (GB) polyps, which can be useful in deciding the treatment of the patient. Methods: One hundred and eighty-seven patients underwent cholecystectomy for GB polyps of around 10 mm for 10 years, and were divided into two groups, cholesterol polyps (146 patients) and non-cholesterol polyps (41 patients) based on the postoperative pathological findings. Gender, age, body weight, height, body mass index (BMI), symptoms, laboratory findings, size, number of polyps, presence of GB stone and maximum diameter measured by preoperative ultrasonography (USG), computed tomography (CT), and pathological diameter were subjected to comparative analysis. Results: Patients diagnosed with cholesterol polyps were younger in age and had higher BMI, and the total cholesterol levels and white blood cell levels were higher, but were not statistically significant. It was notable to see that 28.6% of the cholesterol polyps were not found in the preoperative CT yet the percentage of the undetectable rate was significantly lower (8%) in the non-cholesterol polyp group. There was a discrepancy in maximum diameters between the two radiological methods in both groups but the discrepancy was significantly larger in the cholesterol polyp group. Conclusion: The clinical signs that can be helpful to diagnose whether it is a cholesterol polyp or not are younger patients who have high BMI, polyps which are detectable only on the USG and large maximum diameters between the USG and CT. And if the discrepancy of the maximum diameter is lesser than 1mm the polyp may be considered as a non-cholesterol polyp.

J적분을 이용한 뼈와 유사한 재료의 파괴 해석

이창우(Chang Woo Lee),Song Lin,범현규(Hyeon Gyu Beom) Korean Society for Precision Engineering 2010 한국정밀공학회지 Vol.27 No.9

The analysis of a crack in a bone-like material is performed numerically. The bone-like material is hierarchically structured and each hierarchy is structured by mineral platelets and protein matrix through staggered arrangement. Mechanical behavior of the composite can be analyzed using tension shear chain model. The Dugdale model is adopted to evaluate the fracture energy of Bone-like material. The fracture energy dissipation is assumed to concentrate within a strip near the crack tip along the prospective crack path. Fracture criterion of the bone-like material is estimated by using J integral. Effects of hierarchical level, ratio of elastic modulus of mineral to protein, aspect ratio of mineral platelet and volume fraction on J integral are investigated. It is found that the J integral decreases as elastic modulus ratio and hierarchy level increase. It is also shown that the J integral increases as the volume fraction and aspect ratio decrease.

Influences of heating processes on properties and microstructure of porous CeO2 beads as a surrogate for nuclear fuels fabricated by a microfluidic sol-gel process

Tong Song,Lin Guo,Ming Chen,Zhen-Qi Chang 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.1

The control of microstructure is critical for the porous fuel particles used for infiltrating actinide nuclides. This study concerns the effect of heating processes on properties and microstructure of the fuel particles. The uniform gel precursor beads were synthesized by a microfluidic sol-gel process and then the porousCeO2 microspheres, as a surrogate for the ceramic nuclear fuel particles, were obtained by heatingtreatment of the gel precursors. The fabricated CeO2 microspheres have a narrow size distribution andgood sphericity due to the feature of microfluidics. The effects of heating processes parameters, such asheating mode and peak temperatures on the properties of microspheres were studied in detail. Anoptimized heating mode and the peak temperature of 650 C were selected to produce porous CeO2microspheres. The optimized heating mode can avoid the appearance of broken or crack microspheres inthe heating process, and as-prepared porous microspheres were of suitable pore size distribution andpore volume for loading minor actinide (MA) solution by an infiltration method that is used for fabricationof MA-bearing nuclear fuel beads. After the infiltration process, 1000 C was selected as the finaltemperature to improve the compressive strength of microspheres.

SYNTHESIS AND CHARACTERIZATION OF TITANIA NANOTUBES FOR DYE WASTEWATER TREATMENT

KUEN-SONG LIN,CHAO-CHUN LO,NI-BIN CHANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.4

This paper starts with the preparation of anatase titania nanotube (TN) in large quantities by hydrothermal routes with different calcination temperatures, and then delves into a thorough investigation for the characterization of fine structures or formation mechanism of TN. Experimentally, anatase TiO2 nanoparticle was used as a precursor for TN synthesis. The results showed that the length and diameter of TN range are 50–100 nm and 10–15 nm, respectively. The XRD patterns and BET isotherms indicated that TN owns anatase-typed structures with a surface area of 292m2/g. By extended X-ray absorption fine structure (EXAFS) spectra, the valency and framework of TN are Ti(IV) with octahedral structures. The EXAFS data also revealed that TN has a first shell of Ti–O bonding with bond distances of 1.95 Å and coordination numbers were 2. The results revealed that the TiO2 anatase nanoparticles can be solved into layer under strong alkaline. The layer of TN further curling itself to reduce the energetics was postulated and found. For calcination temperature larger than 400°C, the microstructure of TN might transform from nanotube into nanoparticles accompanying with the sharp increase for the nanoparticle crystalline phase. With the understanding of pore structure variation on the basic dye (Basic Green 5 (BG5)), the adsorption ability, mechanisms, and kinetics of (Basic Green 5 (BG5)) dye onto TN were examined as well.

DECONTAMINATION OF NITRATES AND NITRITES IN WASTEWATER BY ZERO-VALENT IRON NANOPARTICLES

KUEN-SONG LIN,TIEN-DENG CHUANG,NI-BIN CHANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.4

The chemical reduction of nitrate or nitrite species by zero-valent iron nanoparticle (ZVIN) in aqueous solution and related reaction kinetics or mechanisms using fine structure characterization were investigated. Experimentally, ZVIN of this study was prepared by borohydride reduction method at room temperature. The morphology of as-synthesized ZVIN shows that the nearly ball and ultrafine particles ranged of 20–50 nm were observed with FE-SEM analysis. The kinetic model of nitrites or nitrates reductive reaction by ZVIN is proposed as a pseudo-first-order kinetic equation. The nitrite and nitrate removal efficiencies using ZVIN were found 65–83% and 51–68%, respectively, based on three different initial concentrations. By using XRD patterns, the quantitative relationship between nitrite and Fe(III) or Fe(II) becomes similar to the one between nitrate and Fe(III) in the ZVIN study. The possible reason is linked with a faster nitrite reduction by ZVIN. In fact,the occurrence of the relative faster nitrite reductive reaction suggested that the passivation of the ZVIN have a significant contribution to iron corrosion. The XANES spectra show that the nitrites or nitrates reduce to N₂ while oxidizing the ZVIN to Fe₂O₃ or Fe₃O₄ electrochemically. It is also very clear that decontamination of nitrate or nitrite species in groundwater via the in-situ remediation with a ZVIN permeable reactive barrier would be environmentally attractive.

Implementation of 3D Human Simulation to the Design of the Design of μ-Assembly Machine

Bing Lin Zhang(장병림),Guan Wang(왕관),Dug Hee Moon(문덕희),Jun-Yeob Song(송준엽),Chang Woo Lee(이창우) 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-

This paper describes a case study of applying 3D human simulation to the design of a u-assembly machine which is a micro semi-automatic machine. Two types of assembly machine are tested and compared. The purpose of our research is to find out a better design considering ergonomics through the implementation of 3D human simulation and RULA analysis. The worker's working postures are analyzed during the simulation of assembly process.

Is the Daily Price Limit of the Taiwan Stock Exchange Effective? Fundamentals of Listed Stocks and Investors` Perception of Fair Price

Chih Hsiang Chang,Song Lin Hsieh 한국증권학회 2008 Asia-Pacific Journal of Financial Studies Vol.37 No.4