• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.324-324
• /
• 2023

수제는 비용 대비 높은 효율을 가지는 수공 구조물로 하천과 해안에 많이 이용된다. 수제는 하천에서 식생물의 서식처, 유량 확보, 하천시설 보호 등의 목적으로 설치되며 해안에서는 해안선보호, 수심 확보 등의 다양한 목적으로 설치된다. 수제는 일반적으로 넓은 영역을 제어할 수 있도록 여러개의 군수제 형태로 설치한다. 수제설치 시 기존 하도나 수로의 흐름에 교란이 일어나는데 본류부에서는 하폭이 좁아져 수제선단부에 의한 영향으로 높은 유속이 발생되며 수제역내에서는 재순환흐름과 함께 다양한 형태의 유속분포가 형성된다. 이러한 수제에 의한 흐름은 수제 선단부의 영향으로 발생하는 흐름분리선(Separation Layer)을 기준으로 흐름중심선(Talweg Line)과 흐름분리영역(Separation area)을 만들어내며 수제역내의 재순환영역에서 완화된 유속은 제방을 침식으로부터 보호하며 식생물의 서식처를 제공한다. 기존의 연구는 대부분 단일수제에 대한 연구가 수행되었으며 연속된 군수제에 대한 연구는 다소 제한된 조건에서 수행되었다. 이에 본 연구에서는 연속된 수제가 설치된 경우 수리실험을 통해 수제주변의 흐름 변화 특성을 분석하였다. 수리실험은 30.0m(L')×1.52m(B')×1.10m(H')의 직선 개수로에 050m(l)×0.10m(b)×0.25m(h)의 수제를 수로측면을 따라 연속적으로 배열하여 설치하였다. 실험은 수심, 유량, 수제설치간격을 변화시키면서 수행했으며 마그네틱유속계를 사용해서 수제의 영향을 받지 않으며 벽면의 영향이 가장 적은 수로상류의 중앙지점에서 접근유속을 측정했다. 표면유속을 취득하기 위해 일반디지털카메라로 FHD(1920×1080) 해상도를 가진 영상을 각각의 조건마다 10~20분 촬영했다. 촬영된 영상을 연속된 정지영상으로 변환하고 영상해석 프로그램을 이용하여 표면유속을 도출했다. 표면영상유속계를 활용하여 도출한 결과로 각각 조건에 따라 발생하는 최대유속과 최대역방향유속, 와도(vorticity), 흐름중심선과 단면유속분포의 변화와 발생 위치를 분석했다.

• Journal of the Korean Society of Radiology
• /
• v.17 no.4
• /
• pp.607-614
• /
• 2023

Clear overlapping of the bilateral epicondyle and proper separation of the elbow joint are crucial for obtaining accurate lateral general radiographs of the elbow. However, due to the complex anatomical structure of the elbow, achieving optimal positioning is challenging, leading to the need for repeated x-ray examinations. Therefore, the purpose of this study was to investigate the angle of the forearm in patients where accurate lateral images of the elbow joint can't be obtained after vertical incidence using a styrofoam device during elbow joint lateral x-ray imaging. Twenty patients were enrolled in our study following the established protocol. First, a vertical x-ray at an angle of 0° between the forearm and the table was taken (control group). Here, if the lateral image of the elbow joint was deemed inadequate, the forearm angle was adjusted using custom-made styrofoam supports with 5° and 10° inclinations (experimental groups). For the evaluation method, two assessors utilized a 5-point Likert scale to assess the images. The reliability of the assessments was analyzed using Cronbach's alpha coefficient. As a result, patients with inadequate overlap of the bilateral epicondyle and separation of the elbow joint in the initial examination (control group) were able to obtain the best images when setting a 10° angle between the forearm and the table. The subjective evaluation was 1.6 ± 0.8 points at 0°, 2.7 ± 0.8 points at 5°, and 4.4 ± 1.3 points at 10°, respectively. The reliability analysis for the angles of 0°, 5°, and 10° yielded Cronbach's alpha values of 0.867, 0.697, and 0.922, respectively. In conclusion, when it is not possible to obtain accurate images using the conventional position and X-ray beam direction, it is considered that by initially acquiring images with an angle of 10° between the forearm and the table, and gradually decreasing the angle while obtaining images, it would be possible to achieve the optimal image while reducing the number of repeat examinations.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.38 no.1
• /
• pp.43-57
• /
• 2002

This paper introduces an analysis method to predicting the flow characteristic of flow field around otter board In order to develope a high performance model. In this experiment, it is used a numerical analysis of flow field through CFD(Computational Fluid Dynamic), PIV method in which quantitative, qualitative evaluation is possible. In this experiment, it is used PIV method with flow filed image around otter board in order to analysis of flow characteristic. The result compared flow pattern with analysis result through CFD and also measurement result of lift and drag force coefficient carried out in CWC(Circulating Water Channel). The numerical analysis result is matched well with experiment result of PIV in the research and it is able to verify In the physical aspect. The result is as follows ; (1) It was carried out visibility experiment using laser light sheet, and picture analysis through PIV method in order to analysis fluid field of otter-board. As a result, the tendency of qualitative fluid movement only through the fluid particle's flow could be known. (2) Since PIV analysis result is quantitative, this can be seen in velocity vector distributions, instantaneous streamline contour, and average vorticity distributions through various post processing method. As a result, the change of flow field could be confirmed. (3) At angle of attack 24$^{\circ}$ where It Is shown maximum spreading force coefficient, the analysis result of CFD and PIV had very similar flow pattern. In both case, at the otter-board post edge a little boundary layer separation was seen, but, generally they had a good flow (4) As the result of post processing with velocity vector distributions, instantaneous streamline contour and average vorticity distributions by PIV, boundary layer separation phenomenon started to happen from angle of attack 24$^{\circ}$, and from over angle of attack 28$^{\circ}$, it happen at leading edge side with the width enlarged.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.7
• /
• pp.80-86
• /
• 2019

As computer performance improves, research using deep learning are being actively carried out in various fields. Recently, deep learning technology has been applying to the safety evaluation for structures. In particular, the internal blades of a turbine structure requires experienced experts and considerable time to detect surface damages because of the difficulty of separation of the blades from the structure and the dark environmental condition. This study proposes a Faster R-CNN deep learning model that can detect surface damages on the internal blades, which is one of the primary elements of the turbine structure. The deep learning model was trained using image data with dent and punch damages. The image data was also expanded using image filtering and image data generator techniques. As a result, the deep learning model showed 96.1% accuracy, 95.3% recall, and 96% precision. The value of the recall means that the proposed deep learning model could not detect the blade damages for 4.7%. The performance of the proposed damage detection system can be further improved by collecting and extending damage images in various environments, and finally it can be applicable for turbine engine maintenance.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.3
• /
• pp.179-185
• /
• 2019

This paper proposes a block-type classification based image binarization for the implementation of the low-power feature extraction algorithm. The proposed method can be implemented with threshold value re-use technique approach when the image divided into $64{\times}64$ macro blocks size and calculating the threshold value for each block type only once. The algorithm is validated based on quantitative results that only a threshold value change rate of up to 9% occurs within the same image/block type. Existing algorithms should compute the threshold value for 64 blocks when the macro block is divided by $64{\times}64$ on the basis of $512{\times}512$ images, but all suggestions can be made only once for best cases where the same block type is printed, and for the remaining 63 blocks, the adaptive threshold calculation can be reduced by only performing a block type classification process. The threshold calculation operation is performed five times when all block types occur, and only the block type separation process can be performed for the remaining 59 blocks, so 93% adaptive threshold calculation operation can be reduced.

• Journal of the Korean Society of Radiology
• /
• v.7 no.2
• /
• pp.107-112
• /
• 2013

There is an Ankle Oblique(Broden' low) as an examination for the patient whose ankle was encased in orthopedic plaster. Some types of Ankle Joint coalition - Calcaneonavicular coalition, Talocalcaneal coalition and Naviculocuneiform coalition. This study is focused on the relation between Ankle Joints and the structural change of soft tissues, also finding the most proper angle to obtain good images of Ankle Joint from the patient who wore a plaster on his ankle, when we x-ray with Harris-Beath View($30^{\circ}{\sim}55^{\circ}$) - for observing Subtalar joint, Calcaneus Fracture, Subtentaculum, Tali Fracture and Talocalcaneal coalition. We intend to get the angle which makes us achieve the good image that shows Calcaneus Fracture, Subtentaculum, and Tali Fracture by changing internal angles of the patient's ankle. We evaluated the images obtained from 51 patients with PACS monitor. The result of the evaluation, subtalar joint was not seperated but opened, and Subtentaculum Tali Fracture was seen overlaid. at the angle 30, we could observe Calcaneus Fracture, Subtentaculum Tali Frature and the front part of behind side of subtalar joint well. And Calcaneo Navicularcoalition, Talocal Canealcoalition, Naviculo Cuneiform coalition condition were clearly seen at that angle. At the angle 35, we could achieve the clear images of subtalar comminuted fracture, talus, the behind joint of heel bone and get the high definition image on the degree of talocalcaneal joint separation. In addition to, We could obtain the good wide image of Sinus Tarsi. At the area of 45, We can distinguish the soft tissues from gyps separation. The outer-talus and density of the bone were definitely seen and Calcaneus is more separated than that of at the angle of 35, but this image is distorted. Calcaneus, Subtentaculum Tali show $1.20{\pm}0.414$ at the angle 25, $2.47{\pm}0.516$ at the angle 30, $2.27{\pm}0.458$ at the angle 45. This difference is statistically meaningful. (p<0.05). Including the degree of distortion, The distortion appears less at the area of $30^{\circ}$ but at the area of 40, there is heavy distortion. So, We could get the best image for making a diagnosis. At the $30{\sim}35^{\circ}$ degree for X-raying ankle. and at the $30{\sim}40^{\circ}$ for Calcaneus Fracture, Subtentaculum Tali Fracture.

• Journal of Periodontal and Implant Science
• /
• v.34 no.2
• /
• pp.281-292
• /
• 2004

Periodontal defects of the furcation are characterized by several inherent anatomic factors that can make successful periodontal therapy difficult and results unpredictable. The severity and rate of occurrence of periodontal disease are directly related to the location of the furcation relative to the cementa-enamel junction and anatomical form of the root by limiting the accessibility and effectiveness of the periodontal instrumentation. This study investigated the reliability and accuracy of panoramic radiograph diagnoses of the periodontal state of mandibular molars, particularly regarding the diagnosis of furcation area periodontal defects, treatment planning, and prognosis prediction. This study examined a total of 110 teeth belonging to 33 subjects (19 male, 14 female) presenting with incipient to moderate periodontitis 4-7mmpocket depth. The alveolar bone level, length and width of the root trunk, and root separation angle were measured using the panoramic radiograph and compared to the results taken directly by retracting a full-thickness flap. The results of the study are as follows: 1. Data regarding the alveolar bone level of the mandibular first molar showed that the directly taken surgical measurements resulted in $5.1{\pm}0.9mm$ that was slightly deeper than the corresponding panoramic measurement resulted in $4.8{\pm}0.8mm$, but these differences were statistically insignificant (p>0.05). 2. The data of the directly taken surgical measurement of the mandibular second molar $(5.1{\pm}1.1mm)$ was slightly deeper than the corresponding panoramic measurement $(4.7{\pm}1.2mm)$, but these differences were statistically insignificant (p>0.05). 3. The measured values of the length and width of the mandibular first molar root trunks were determined to be $4.1{\pm}0.6mm$ and $7.3{\pm}0.9mm$, respectively, while the values of the mandibular second molar root trunks were determined to be $4.6{\pm}1.3mm$ and $7.6{\pm}0.9mm$ respectively. The differences between these values were found to be statistically significant (p<0.01). 4. The measured values of the root separation angle showed that the mandibular first molars averaged $34.5{\pm}4.4^{\circ}$, while the mandibular second molars averaged $23.0{\pm}10.0^{\circ}$. The differences between these values were found to be statistically significant (p<0.01).

• Membrane Journal
• /
• v.18 no.3
• /
• pp.206-213
• /
• 2008

Poly(vinylidene fluoride) (PVDF) membrane surfaces were modified using surface modifying macromolecules (SMMs). The Zonyl BA-L as SMM was used and the various PVDF membranes containing 0 to 2 wt% SMM were prepared. The resulting membranes were characterized through SEM, contact angle measurements and pervaporation separation of water-ethanol system. SMM layers were created in the surface regions of PVDF membranes by SEM images and the contact angles were increased more than untreated PVDF membranes. The pervaporation was carried out at 50, 60 and $70^{\circ}C$, and the PVDF membranes containing 1 and 2 wt% SMM were used for 10, 20, 50 wt% water in the binary water/ethanol mixtures and pure water. PVDF/2 wt% Zrlnyl BA-L membrane showed the permeability 5.3 $g/m^2hr$ and separation factor 287 at $50^{\circ}C$ for water : ethanol = 10 : 50 solution.

• Health Policy and Management
• /
• v.12 no.4
• /
• pp.91-113
• /
• 2002

We report and analyze the Korean physicians' recent general strike over the implementation of the Separation of Prescribing and Dispensing Practice (SPDP) in which more than 18,000 private clinics and 280 hospitals participated. Utilizing game-theoretic models of bargaining we explain why the Korean physicians were so successful in organizing intense collective action against the government and securing very favorable policy outcomes. In particular, we highlight the role of distributional conflict among social actors in shaping the details of institutional reform. The introduction of the SPDP was a necessary first step in the overall reform of health care system in Korea. However, the SPDP was perceived to be a serious threat to the economic viability of their profession by the vast majority of Korean physicians who had long been relied on the profits from selling medicines to compensate for the loss of income due to the low service fee under the previous health care system. The strong political coalition among heterogeneous physicians enabled them to organize an intense form of collective action, the general strike. Thus, physicians were successful not only in dragging the government to a bargaining table, but also winning in the bargaining and securing an outcome vastly favorable to them. On the other hand, the lack of an overall reform plan in the health care policy area, especially the finance of the National Health Insurance and the need for maintaining an image as a successful reform initiator, motivated the government to reach a quick resolution with the striking physicians.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.42 no.4 s.304
• /
• pp.49-59
• /
• 2005

This paper proposed a six-color separation using additional colorants and quantitative granularity metric to reduce color difference and graininess. In the conventional method, light magenta and light cyan are used in the bright region instead of magenta and cyan. However, the hue value of liBht magenta and light cyan is different from the one of magenta and cyan in CIELAB space, so that this makes the colorimetric reproduction more or less inaccurate. To improve this inaccuracy, the proposed method uses yellow and light magenta colorants as the additional colorants. In the bright region, magenta is replaced with light magenta and yellow, while cyan is replaced with light cyan and light magenta. This selection reduces hue difference because it creates the color of similar hue to magenta and cyan. In addition, smooth image can be simultaneously obtained by the less dot visibility of additional colorants. In the middle region, magenta is replaced with light magenta and magenta, while cyan is replaced with light cyan and cyan. The use of two colorants having a different concentration makes the dot Pattern coarse. To reflect this Phenomenon, quantitative granularity metric is used. In the dark region, only magenta and cyan colorant is used as usual. Through experiments, it is shown that the proposed method improves both colorimetric and smooth tone reproductions.