• Korean Journal of Optics and Photonics
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• v.25 no.4
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• pp.193-199
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• 2014

The net effect of the emitter orientation, Mie scatters, and pillow lenses on the outcoupling efficiency (OCE) of a bottom-emitting OLED having an internal photonic crystal layer was investigated by a combined optical simulation based on the finite-difference time-domain method (FDTD) and the ray-tracing technique. The simulation showed that when the emitter orientation was horizontal with respect to the OLED surface, the OCE could be increased by 54% when a photonic crystal layer was employed, while it could be improved by 86% under optimized conditions of Mie scatters and pillow lenses applied to the glass substrate. The peculiar intensity distribution of the OLED, caused by the periodic lattice structure of the photonic crystal layer, could be ameliorated by inserting Mie scatters into the glass substrate. This study suggests that conventional outcoupling structures combined with control of the emitter orientation could improve the OCE substantially.

• Applied Microscopy
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• v.15 no.2
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• pp.98-110
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• 1985

This study was performed to clarify the morphological structures of the epithelia of the renal papilla, renal pelvis and ureter of the sheep (Ovis aries L.) through the light and scanning electron microscopes, Tissue specimens were taken from the renal papilla (common renal papilla and peripelvic column) and the renal pelvis (pelvis proper and pelvic pouch) of the kidney and the ureter. For the light microscopy, tissue blocks were fixed in 10 % neutral buffered formalin and embedded in paraffin wax, serially sectioned at a thickness of $6{\mu}m$. These sections were stained with hematoxylin-eosin and periodic acid-Schiff reaction. For the scanning electron microscopy, tissue blocks were prefixed in 1% glutaral-dehyde-1.5% paraformaldehyde solution and postfixed in 1% osmium tetroxide solution, dehydrated in graded alcohol, transferred to isoamyl acetate, and then dried by the critical point dryer (Polaron E 3000). These dried tissues were coated with gold and observed with a scanning electron microscope (JSM-35C), The results were as follows: The apex of the common renal papilla was lined with simple columnar epithelium having many microvilli on its luminal surface. Lateral portion of the papilla was lined with stratified epithelium $2{\sim}3$ layers thick, and its superficial cells were microvillar cells having many microvilli. The epithelium lining the peripelvic column was $1{\sim}2$ layers thick. The superficial layer was made of the microvillar cells, but a few microplica cells were appeared in the region near the pelvic pouch. The epithelium of the pelvic pouch was $1{\sim}2$ layered transitional type, and its superficial cells were microplica cells. The epithelia of the pelvis proper and ureter were $4{\sim}6$ layered transitional type, and their superficial cells were typical facet cells existing many round depressions and ridges of cell membranes of the luminal side.

• Journal of Animal Environmental Science
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• v.16 no.1
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• pp.13-20
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• 2010

Manure compost is a main product from animal wastes in Korea. Solid manure is usually treated by aerobic composting at manure composting facilities for land reinforcement. Agricultural use of manure compost as organic fertilizer resources, mainly manure compost, is now recommended in Korea. This study investigated the evaluation of durability about the manure composting machinery and structures which was controlled by aeration and periodic agitating. The questionnaire addressed three main topics as follows: operating practices, machinery and maintenance of the manure composting facilities are being operated. A total of the 22 manure composting facilities in an agricultural cooperative were surveyed. The results obtained in this survey were summarized as follow: The major causes of manure composting apparatus trouble were corrosion and wear, overloading and foreign matter etc. The highly trouble frequency of the agitator, packer and conveyor were chain, agitating blade and shaft, motor and screw vane, respectively. These analytical results can be used as basic information to establish the maintenance control methods and durability standard of manure composting facility.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.186-190
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• 2008

This paper analyzes previous work on publish/subscribe in mobile ad-hoc networks with respect to collaboration methods among distributed event brokers. Our experiments suggest that approaches building event delivery structures are suitable for a scenario where there are events of various types each of which is consumed by a few subscribers. However, these approaches based on independent periodic exchange of network topology information may fail to reflect the up-to-date information when building event delivery paths. For this reason they do not correctly recover a broken path caused by node mobility, which results in lower event delivery rates. This paper proposes a scheme for building and maintaining event delivery paths based on advertisements initiated by and hence propagated from the root node. This guarantees correct recovery of event delivery paths within each period. Our experiments show that, our proposed scheme gives a better event delivery ratio with lower overhead.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.241-247
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• 2019

A band gap refers to a certain frequency range where the propagation of mechanical waves is prohibited. This work focuses on engineering three-dimensional Kelvin lattices having external band gaps at low audible frequency ranges using a gradient-based design optimization method. Elastic wave propagation in an infinite periodic lattice is investigated by employing the Bloch theorem. We model the ligaments using a shear-deformable beam model obtained by consistent linearization in a geometrically exact beam theory. For a given lattice topology, we enlarge band gap sizes by controlling the configuration of the beam neutral axis and cross-section thickness that are smoothly parameterized by B-spline basis functions within the isogeometric analysis framework.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.321-327
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• 2022

In this paper, a wrinkled structure was formed on the PDMS surface through UV/Ozone treatment, and the wrinkle structure formation mechanism was revealed through physicochemical characterization. A wrinkle structure was formed on the PDMS surface through UV/Ozone treatment for 30 min, and periodic wrinkle formation on the PDMS surface was confirmed by cross-sectional imaging of the scanning electron microscope. In addition, through x-ray photoelectron spectroscopy spectral analysis, it was confirmed that the silica-like-surface of SiOx on the PDMS surface was formed by UV/Ozone. The results of this study not only improve the understanding of the mechanism of wrinkle structure formation on the PDMS surface by UV/Ozone treatment, but also can be used as a basic study to adjust the amplitude and period of the wrinkle structure according to UV/Ozone irradiation conditions in the future.contact angles and the surface energies of FSAMs, it was confirmed that pretilt angles of LC molecules increased according to the alkyl chain length. High optical transparency and uniform homeotropic LC alignment characteristics of FSAMs showed the possibility of FSAMs as an LC alignment layers.

• Smart Structures and Systems
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• v.31 no.4
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• pp.335-349
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• 2023

Bridges constantly undergo deterioration and damage, the most common ones being concrete damage and exposed rebar. Periodic inspection of bridges to identify damages can aid in their quick remediation. Likewise, identifying components can provide context for damage assessment and help gauge a bridge's state of interaction with its surroundings. Current inspection techniques rely on manual site visits, which can be time-consuming and costly. More recently, robotic inspection assisted by autonomous data analytics based on Computer Vision (CV) and Artificial Intelligence (AI) has been viewed as a suitable alternative to manual inspection because of its efficiency and accuracy. To aid research in this avenue, this study performs a comparative assessment of different architectures, loss functions, and ensembling strategies for the autonomous segmentation of bridge components and damages. The experiments lead to several interesting discoveries. Nested Reg-UNet architecture is found to outperform five other state-of-the-art architectures in both damage and component segmentation tasks. The architecture is built by combining a Nested UNet style dense configuration with a pretrained RegNet encoder. In terms of the mean Intersection over Union (mIoU) metric, the Nested Reg-UNet architecture provides an improvement of 2.86% on the damage segmentation task and 1.66% on the component segmentation task compared to the state-of-the-art UNet architecture. Furthermore, it is demonstrated that incorporating the Lovasz-Softmax loss function to counter class imbalance can boost performance by 3.44% in the component segmentation task over the most employed alternative, weighted Cross Entropy (wCE). Finally, weighted softmax ensembling is found to be quite effective when used synchronously with the Nested Reg-UNet architecture by providing mIoU improvement of 0.74% in the component segmentation task and 1.14% in the damage segmentation task over a single-architecture baseline. Overall, the best mIoU of 92.50% for the component segmentation task and 84.19% for the damage segmentation task validate the feasibility of these techniques for autonomous bridge component and damage segmentation using RGB images.

• International Journal of Highway Engineering
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• v.19 no.3
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• pp.19-30
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• 2017

PURPOSES : This study proposes the road asset valuation approach using alternative depreciation methods. It has become necessary to have asset management system according to the adoption of accrual basis accounting for governmental financial reporting and the amendment of the road act. Therefore, it is very important to analyze the effect of depreciation methods on road asset value as a basic research for road asset management system. METHODS : The Ministry of Strategy and Finance (MOSF) has mainly performed road asset valuation based on Write down Replacement Cost and Straight Line depreciation method. This study suggests some appropriate asset valuation methods for road assets through case analysis using three depreciation methods: Consumption-based depreciation method, Condition-based depreciation method, and Straight Line depreciation method. A road asset valuation data of national highway route 1 (year 2014) is used to analyze the effect of three depreciation methods on the road asset value. Road assets include land and structures (pavement, bridge, and tunnel). This study mainly focuses on structures such as bridges and tunnels, because according to governmental accounting standards, land and road pavement assets do not depreciate. RESULTS : The main results of this study are as follows. Firstly, overall asset value of national highway route 1 was estimated at 6.97 trillion KRW when MOSF's method (straight-line depreciation method) is applied. Secondly, asset value was estimated at 4.85 trillion KRW on application of consumption-based depreciation method. Thirdly, asset value was estimated at 4.37 trillion KRW when condition-based depreciation method is applied. Therefore, either consumption-based or condition-based depreciation methods would be more appropriate than straight-line depreciation method if we can use the condition data of road assets including land that are available in real time. CONCLUSIONS : Since road assets such as pavements, bridges, and tunnels have various patterns of deterioration and condition monitoring period, it is necessary to consider a specific valuation method according to the condition of each road asset. Firstly, even though road pavements do not depreciate, asset valuation through condition-based depreciation method would be more appropriate when requirements for application of non-depreciation approach are not satisfied. Since bridge and tunnel facilities show various patterns of deterioration and condition monitoring period by type and condition level, consumption-based depreciation method based on deterioration model would be appropriate. Therefore, it is necessary to have a reasonable asset management system to apply condition-based depreciation method and a periodic condition investigation to manage road assets well.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.1-12
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• 2012

This study aims to suggest ways to improve sustainability on housing complexes. This study sampled eight housing projects in Seoul and GyeongGi-Do in Korea, which were completed in June 2007 and June 2008. Then, are retention and maintenance on "constructed greens for ecological environment" including "green structures substitutes retaining walls", "green roofs", and "green walls." Study methods are field investigations of the sampled sites, and Post Occupancy Analysis. Major findings were; 1) "constructed greens" are not well retained in more sites and and this implies the GBCS(Green Building Certification System) does not meet its objectives well, 2) User showed lower user satisfaction to "constructed greens". User satisfaction concerning "green structures substitute retaining walls" was higher than the satisfaction on the other constructed green type. Satisfaction Assessment Criteria lower 1han average were "level of quality", "meet the design objectives", "vegetation management status", "vegetation maintenance". 3) User satisfaction was strongly correlated on the level of quality factor of "constructed green". In addition, tue other factors are the significant correlations between the satisfactions. The present GBCS has inadequate assessment standards for maintenance, which lead to lower the entire satisfaction. Therefore, periodic recertification system, education and information providing for the managing personals, and incentives for good maintenance or disincentive for poor maintenance of the "constructed greens" are suggested to improve the GBCS.

• Journal of Oral Medicine and Pain
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• v.33 no.4
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• pp.387-394
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• 2008

Purpose : The purpose of this study was to verify the usefulness and feasibility of ultrasonographic imaging for the detection of the disorders of the surrounding supporting structure such as articular capsule, retrodiscal tissue and related ligaments, osteoarthritic evidence and associated disc displacement at the temporomandibular joint(TMJ) Materials and Methods : 20 patients(40 joints) with periodic lock and crepitations were investigated prospectively using 12 MHz array transducer. Ultrasonographic Imagings were assessed for osteoarthritic surface changes of condyle, extent of disc displacement and disorders of surrounding structures. Ultrasonographic images were compared with clinical investigations, conventional radiography and Dental Computed Tomographic scans. Results : In clinical and conventional radiography, osteoarthritic changes were diagnosed in 8 joints. Ultrasonographically 7 of the 8 osteoarthritic changes were diagnosed correctly. Sensitivity, specificity, and accuracy of ultrasonography in the osteoarthritic detections were 87.5%, 62.5%, and 67.5% respectively. About the detection of disc displacement, disc displacement were diagnosed in 21 joints clinically. Ultrasonographically 19 of the 21 disc displacements were diagnosed correctly. Sensitivity, specificity, and accuracy of ultrasonography in the osteoarthritic detections were 95%, 90%, and 92.5% respectively. when the disorders of supportive structure were figured out, the disorders of supportive structure were diagnosed in 18 joints clinically. Ultrasonographically 1 of the 18 the disorders of supportive structure were diagnosed correctly. Sensitivity, specificity, and accuracy of ultrasonography in the osteoarthritic detections were 5.5%, 4.5%, and 55% respectively. Conclusion : Ultrasonography is an relatively reliable diagnostic tool for the detection of disc displacement and some of osteoarthritic changes. But it's not an insufficient imaging technique for the detection of the disorders of the surrounding structure.