• Corrosion Science and Technology
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• 제2권4호
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• pp.202-206
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• 2003

Fusion Bonded Epoxy(FBE) systems have been widely used to protect pipelines for over 30 years. Numerous attempts have so far been made to improve the properties of FBE coatings such as chemical resistance, adhesion, water resistance, cathodic disbondment resistance, impact resistance, and flexibility to protect pipelines at a wet and a high temperature condition. But these attempts have not been successful in reducing some weakness, for instance, in pipeline operating at high temperature due to poor hot water resistance and cathodic protection. The purpose here is to build a basis for getting better corrosion resistance of FBE systems. Cresol-novolac epoxy coating systems were studied compared to bisphenol A type epoxy systems. After the immersion of the film in water at a high temperature for a long period, good adhesion to metal substrate and excellent cathodic disbond resistance were observed in the cresol-novolac epoxy resin systems. It is well known that the adhesion of organic coatings to metal substrate might be decreased due to the disruption of a chemical bond across the film and metal interface induced by water molecules. A high crosslinking density might decrease water permeability and improve cathodic disbonding protection in the coatings. Other factors are studied to understand anti-corrosion mechanism of Cresol-novolac epoxy coatings. In addition, the water absorption rate and the effect of cure temperature on the adhesion and cathodic disbonding resistance ofthe films were studied in different epoxy coatings and the effect of substrate was evaluated. The results of field application are proved that the Cresol-novolac epoxy coating system developed recently is one of the most suitable coatings for protection of pipelines.

• Computers and Concrete
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• 제20권5호
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• pp.563-572
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• 2017

Ordinary reinforced concrete (RC) and prestressed concrete bridges are two popular and typical types of short- and medium-span bridges that accounts for the vast majority of all existing bridges. The cost of maintaining, repairing or replacing degraded existing RC bridges is immense. Detecting the abnormality of RC bridges at an early stage and taking the protective measures in advance are effective ways to improve maintenance practices and reduce the maintenance cost. This study proposes a systematic method from influence line (IL) identification to damage detection with applications to RC bridges. An IL identification method which integrates the cubic B-spline function with Tikhonov regularization is first proposed based on the vehicle information and the corresponding moving vehicle induced bridge response time history. Subsequently, IL change is defined as a damage index for bridge damage detection, and information fusion technique that synthesizes ILs of multiple locations/sensors is used to improve the efficiency and accuracy of damage localization. Finally, the feasibility of the proposed systematic method is verified through experimental tests on a three-span continuous RC beam. The comparison suggests that the identified ILs can well match with the baseline ILs, and it demonstrates that the proposed IL identification method has a high accuracy and a great potential in engineering applications. Results in this case indicate that deflection ILs are superior than strain ILs for damage detection of RC beams, and the performance of damage localization can be significantly improved with the information fusion of multiple ILs.

• 한국의류산업학회지
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• 제13권5호
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• pp.806-814
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• 2011

A solar jacket, which utilizes solar energy for generating electricity, is an example of clothing developed by the fusion of multiple technologies; such fusion of technologies can lead to further developments in the clothing industry and other industries in general. Many research institutes and garment manufacturing companies in Europe and America are developing solar garments; various solar-based products manufactured using solar cells, photovoltaic batteries, etc. are being sold at high prices. The purpose of this study was to investigate the development status of solar garments and their application for generating photovoltaic energy; the study also identified the type of design and upper body clothing preferred by Korean in their early 20s. The survey participants were 188 university students aged between 20 and 25. The design of the proposed six types of solar clothing was evaluated and rated; they were then ranked on the basis of the ratings. A survey on the management of solar garments was conducted, and ratings were assigned according to a 5-point Likert scale, with 5 indicating the strong affirmation. The survey results showed that among the six types of clothing, protective clothing (50%) and sportswear (22%) were more preferable than the others (working clothes (16%), casual clothes (3%), everyday wear(6%), and suits(1%)). Among the six proposed designs, the jumper design (22%) and jean jacket design (21%) were preferred over the others (casual jacket (19%), casual jacket I (15%), classic suit (14%), and climbing jacket (9%)). Factorial analysis of the management of solar garments revealed that the most important factors were the properties of the solar cell and time required for battery charging, and the second important factors were clothing weight and comfort.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.3989-4006
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• 2020

The intelligent agriculture monitoring is based on the perception and analysis of environmental data, which enables the monitoring of the production environment and the control of environmental regulation equipment. As the scale of the application continues to expand, a large amount of data will be generated from the perception layer and uploaded to the cloud service, which will bring challenges of insufficient bandwidth and processing capacity. A fog-based offline and real-time hybrid data analysis architecture was proposed in this paper, which combines offline and real-time analysis to enable real-time data processing on resource-constrained IoT devices. Furthermore, we propose a data process-ing algorithm based on the incremental principal component analysis, which can achieve data dimensionality reduction and update of principal components. We also introduce the concept of Squared Prediction Error (SPE) value and realize the abnormal detection of data through the combination of SPE value and data fusion algorithm. To ensure the accuracy and effectiveness of the algorithm, we design a regular-SPE hybrid model update strategy, which enables the principal component to be updated on demand when data anomalies are found. In addition, this strategy can significantly reduce resource consumption growth due to the data analysis architectures. Practical datasets-based simulations have confirmed that the proposed algorithm can perform data fusion and exception processing in real-time on resource-constrained devices; Our model update strategy can reduce the overall system resource consumption while ensuring the accuracy of the algorithm.

• 대한화학회지
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• 제38권6호
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• pp.411-417
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• 1994

난용성 신소재 중의 하나인 파인 세라믹의 분석을 위하여, 알칼리 용융법과 고압 산분해법 등의 시료 전처리법을 유도결합원자발광분석기(ICP-AES)를 이용하여 연구하였다. Al2O3 분말을 분석하여 본 결과, 고압 산분해법이 알칼리 용융법보다 재현성 있는 측정치를 얻을 수 있었다. SiC분말의 경우에서는 고압산분해법으로 처리한 후 Si매트릭스를 Si-F형태로 증발시켜서 분석하여 본 결과 분말 중의 ppm 농도 범위의 불순물들이 매트릭스에 의한 간섭없이 분석되었다. 일본 인증기준물인 JCRM022, JCRM023 초미립 분말을 고압 산분해법으로 분석하여 본 결과, 좋은 재현성과 높은 정확성을 나타내었다.

• Smart Structures and Systems
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• 제12권3_4호
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• pp.251-269
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• 2013

Measurement of deflections of certain bridges is usually hampered by corruption of the GPS signal by multipath associated with passing vehicles, resulting to unrealistically large apparent displacements. Field data from the Gorgopotamos train bridge in Greece and systematic experiments revealed that such bias is due to superimposition of two major effects, (i) changes in the geometry of satellites because of partial masking of certain satellites by the passing vehicles (this effect can be faced with solutions excluding satellites that get temporarily blocked by passing vehicles) and (ii) dynamic multipath caused from reflection of satellite signals on the passing trains, a high frequency multipath effect, different from the static multipath. Dynamic multipath seems to have rather irregular amplitude, depending on the geometry of measured satellites, but a typical pattern, mainly consisting of a baseline offset, wide base peaks correlating with the sequence of main reflective surfaces of the vehicles passing next to the antenna. In cases of limited corruption of GPS signal by dynamic multipath, corresponding to scale distortion of the short-period component of the GPS waveforms, we propose an algorithm which permits to reconstruct the waveform of bridge deflections using a weak fusion of GPS and RTS data, based on the complementary characteristics of the two instruments. By application of the proposed algorithm we managed to extract semi-static and dynamic displacements and oscillation frequencies of a historical railway bridge under train loading by using noisy GPS and RTS recordings. The combination of GPS and RTS is possible because these two sensors can be fully collocated and have complementary characteristics, with RTS and GPS focusing on the long- and short-period characteristics of the displacement, respectively.

• 한국정보통신학회논문지
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• 제21권2호
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• pp.386-394
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• 2017

FANET은 무인 항공기들로 구성된 애드혹 네트워크로서, 무인 항공기 간의 데이터 전달을 위해 3차원 상에 형성된 네트워크이다. 현재까지 이루어진 대부분의 FANET 활용에 대한 연구는 무인항공기에 장착된 카메라 센서를 활용하여 지상으로부터 데이터를 수집하고, 이를 전달하고 처리하여 특정한 목적에 활용하는 것이다. 하지만 인간 신체 영역의 데이터를 수집하고 이를 FANET을 통해 전달하는 WBAN과 FANET의 융합에 관한 연구는 아직 많이 이루어지 않았다. 따라서 본 연구는 데이터 전달을 위한 통신체계가 잘 갖추어져 있지 않은 도서 또는 오지 지역에서 활동하는 사람들의 인체 데이터를 수집하기 위해 WBAN을 구성하고, 수집된 데이터를 FANET을 통해 전달하는 체계를 연구한다. 특히 WBAN과 FANET의 융합 네트워크에서 신체의 응급데이터를 전달하기 위한 가능한 데이터 전달방법을 분석하고, 효율적으로 데이터를 전달할 수 있는 전송 모델을 제안한다.

• 도시과학
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• 제7권2호
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• pp.53-60
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• 2018

Digital Twin is a technology that creates a photocopy of real-world objects on a computer and analyzes the past and present operational status by fusing the structure, context, and operation of various physical systems with property information, and predicts the future society's countermeasures. In particular, 3D rendering technology (UAS, LiDAR, GNSS, etc.) is a core technology in digital twin. so, the research and application are actively performed in the industry in recent years. However, UAS (Unmanned Aerial System) and LiDAR (Light Detection And Ranging) have to be solved by compensating blind spot which is not reconstructed according to the object shape. In addition, the terrestrial LiDAR can acquire the point cloud of the object more precisely and quickly at a short distance, but a blind spot is generated at the upper part of the object, thereby imposing restrictions on the forward digital twin modeling. The UAS is capable of modeling a specific range of objects with high accuracy by using high resolution images at low altitudes, and has the advantage of generating a high density point group based on SfM (Structure-from-Motion) image analysis technology. However, It is relatively far from the target LiDAR than the terrestrial LiDAR, and it takes time to analyze the image. In particular, it is necessary to reduce the accuracy of the side part and compensate the blind spot. By re-optimizing it after fusion with UAS and Terrestrial LiDAR, the residual error of each modeling method was compensated and the mutual correction result was obtained. The accuracy of fusion-based 3D model is less than 1cm and it is expected to be useful for digital twin construction.

• 한국재료학회지
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• 제31권7호
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• pp.420-426
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• 2021

Graphene, a new material with various advantageous properties, has been actively used in various fields in recent years. Applications of graphene oxide are increasing in combination with other materials due to the different properties of graphene oxide, depending on the number of single and multiple layers of graphene. In this study, single-layer graphene oxide and multi-layer graphene oxide are spray coated on polystyrene, and the physicochemical properties of the coated surfaces are characterized using SEM, Raman spectroscopy, AFM, UV-Vis spectrophotometry, and contact angle measurements. In single-layer graphene oxide, particles of 20 ㎛ are observed, whereas a 2D peak is less often observed, and the difference in surface height increases according to the amount of graphene oxide. Adhesion increases with an increase in graphene oxide up to 0.375 mg, but decreases at 0.75 mg. In multi-layer graphene oxide, particles of 5 ㎛ are observed, as well as a 2D peak. According to the amount of graphene oxide, the height difference of the surface increases and the adhesive strength decreases. Both materials are hydrophilic, but single-layer graphene oxide has a hydrophilicity higher than that of multi-layer graphene oxide. We believe that multi-layer graphene oxide and single-layer graphene oxide can be implemented based on the characteristics that make them suitable for application.

• The Korean Journal of Pain
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• 제34권2호
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• pp.193-200
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• 2021

Background: Local anesthetic infiltration at the site of a surgical wound is commonly used to control postoperative pain. In this study, we examined the effectiveness of continuous local infiltration at an abdominal surgical site in patients undergoing anterior lumbar interbody fusion (ALIF) surgery. Methods: Sixty-one patients who underwent ALIF surgery were enrolled. For thirtyone of them, a continuous local anesthetics infiltration system was used at the abdominal site. We collected data regarding the patients' sleep quality; satisfaction with pain control after surgery; abilities to perform physical tasks and the additional application of opioids in the postoperative 48 hours. Results: The On-Q system group showed reduced visual analogue scale scores for pain at the surgical site during rest and movement at 0, 12, 24, and 48 hours; and more was satisfied with pain control management at the first postoperative day (7.0 ± 1.2 vs. 6.0 ± 1.4; P = 0.003) and week (8.1 ± 1.6 vs. 7.0 ± 1.8; P = 0.010) than the control group. The number of additional patient-controlled analgesia (PCA) bolus and pethidine injections was lower in the On-Q group (PCA: 3.67 ± 1.35 vs. 4.60 ± 1.88; P = 0.049 and pethidine: 2.09 ± 1.07 vs. 2.73 ± 1.38; P = 0.032). Patients who used the On-Q system performed more diverse activity and achieved earlier ambulation than those in the control group. Conclusions: Continuous wound infiltration with ropivacaine using an On-Q system may be effective for controlling postoperative pain after ALIF surgery.