• Journal of Biomedical Engineering Research
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• v.43 no.3
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• pp.177-184
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• 2022

The purpose of this study was to present the IMU sensor based trunk stabilization exercise and to evaluate the changes in the muscle activity and thickness with non-specific low back pain patients (N=30). They were classified into two groups; lumbar stabilization exercise using IMU sensor (ILS), (n₁=20) and general lumbar stabilization exercise (GLS), (n₂=10). By comparing the difference between pre and post intervention via trunk muscle activity and muscle thickness, the significant differences were identified. Muscle activity was measured on external oblique (EO), internal oblique (IO), and multifidus (MF) by using surface electromyography (sEMG). Muslce thickness was measured on external oblique, internal oblique, transverse abdominis (TrA), and multifidus (MF) by using ultrasonography. sEMG activity was recorded at right side-bridge position. Each group performed the proposed lumbar stabilization exercise for 30 minutes a day, 5 times a week for 4 weeks. Trunk muscle activity was observed with a significant increase in the IO of ILS (p<.05) and a decrease in the MF of GLS (p<.05). Trunk muscle thickness was significantly increased in left EO and both IO of GLS (p<.05), and also significant increased right EO, both IO, both TrA, and both MF of the ILS (p<.05). In the future, a convergence approach of rehabilitation and engineering is needed to select a sensor suitable for rehabilitation purposes, study the validity and reliability of data, and produce appropriate rehabilitation contents.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.3950-3969
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• 2021

Radio Frequency (RF)-based indoor localization technologies play significant roles in various Internet of Things (IoT) services (e.g., location-based service). Most such technologies require that all the devices comply with a specified technology (e.g., WiFi, ZigBee, and Bluetooth). However, this requirement limits its application scenarios in today's IoT context where multiple devices complied with different standards coexist in a shared environment. To bridge the gap, in this paper, we propose a cross-technology localization approach, which is able to localize target nodes using a different type of devices. Specifically, the proposed framework reuses the existing WiFi infrastructure without introducing additional cost to localize Non-WiFi device (i.e., ZigBee). The key idea is to leverage the interference between devices that share the same operating frequency (e.g., 2.4GHz). Such interference exhibits unique patterns that depend on the target device's location, thus it can be leveraged for cross-technology localization. The proposed framework uses Principal Components Analysis (PCA) to extract salient features of the received WiFi signals, and leverages Dynamic Time Warping (DTW), Gradient Boosting Regression Tree (GBRT) to improve the robustness of our system. We conduct experiments in real scenario and investigate the impact of different factors. Experimental results show that the average localization accuracy of our prototype can reach 1.54m, which demonstrates a promising direction of building cross-technology technologies to fulfill the needs of modern IoT context.

• Smart Structures and Systems
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• v.29 no.1
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• pp.237-250
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• 2022

Structural health monitoring (SHM) plays an important role in ensuring the safety and functionality of critical civil infrastructure. In recent years, numerous researchers have conducted studies to develop computer vision and machine learning techniques for SHM purposes, offering the potential to reduce the laborious nature and improve the effectiveness of field inspections. However, high-quality vision data from various types of damaged structures is relatively difficult to obtain, because of the rare occurrence of damaged structures. The lack of data is particularly acute for fatigue crack in steel bridge girder. As a result, the lack of data for training purposes is one of the main issues that hinders wider application of these powerful techniques for SHM. To address this problem, the use of synthetic data is proposed in this article to augment real-world datasets used for training neural networks that can identify fatigue cracks in steel structures. First, random textures representing the surface of steel structures with fatigue cracks are created and mapped onto a 3D graphics model. Subsequently, this model is used to generate synthetic images for various lighting conditions and camera angles. A fully convolutional network is then trained for two cases: (1) using only real-word data, and (2) using both synthetic and real-word data. By employing synthetic data augmentation in the training process, the crack identification performance of the neural network for the test dataset is seen to improve from 35% to 40% and 49% to 62% for intersection over union (IoU) and precision, respectively, demonstrating the efficacy of the proposed approach.

• Journal of the Korean School Mathematics Society
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• v.25 no.4
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• pp.333-352
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• 2022

This study is aimed at developing the STEAM instruction materials for mathematics subject-based advanced technology and ICT teaching tools. In order to develop the STEAM materials, a PDI model in which the implementation and evaluation steps were simplified to Improvement was used. The developed STEAM materials were revised and supplemented by a group of experts. The subject of the STEAM class material developed in this study is 『Graph! The bridge that connects the past, present and future』 , 『You are the same but different!』 , 『Creating a virtual reality three-dimensional space together』 , 『And making interesting figures』 and 『Cover the roof of the turtle ship!』 . As a suggestion based on the results of this development study, various STEAM education materials should be developed and shared so that STEAM education can be performed in the elementary education field. And for the spread and settlement of STEAM education, the cultivation and expansion of STEAM education capabilities of on-site elementary school teachers or pre-service teachers will be an absolute prerequisite. And this suggests the need for a continuous and long-term approach to follow-up research on STEAM education.

• Journal of the Korean Geotechnical Society
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• v.22 no.10
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• pp.121-129
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• 2006

Stone column is one of the ground improvement systems which is being used for accelerating consolidation and increasing bearing capacity for settlement sensitive structures like load embankments, bridge abutments, oil storage tanks etc. The effects of this method are enhancement of ground bearing capacity, reduction of settlement, prevention of liquefaction and prevention of lateral ground movement. Recently, geosynthetic reinforced (encased) stone column approach has been developed to improve its load carrying capacity through increasing confinement effect. Although such a concept has successfully been applied in practice, fundamentals of the method have not been fully explored. This paper presents the results of an investigation on the bearing capacity and failure mechanism of geogrid-encased stone column by model tests. The results of the analyses indicated improved bearing capacity of the geogrid reinforced stone column method over the conventional strone column method with no encasing.

• Earthquakes and Structures
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• v.22 no.3
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• pp.245-261
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• 2022

Key questions to researchers interested in nonlinear analysis of skeletal structures are whether the distributed plasticity approach - albeit computationally demanding - is more reliable than the concentrated plasticity to adequately capture the extent and severity of the inelastic response, and whether force-based formulation is more efficient than displacement-based formulation without compromising accuracy. The present research focusing on performance-based seismic response of mid-span concrete bridges provides a pilot holistic investigation opting for some hands-on answers. OpenSees software is considered adopting different modeling techniques, viz. distributed plasticity (through either displacement-based or force-based elements) and concentrated plasticity via beam-with-hinges elements. The pros and cons of each are discussed based on nonlinear pushover analysis results, and fragility curves generated for various performance levels relying on incremental dynamic analyses under real earthquake records. Among prime conclusions, distributed plasticity modeling albeit inherently not relying on prior knowledge of plastic hinge length still somewhat depends on such information to ensure accurate results. For instance, displacement-based and force-based approaches secure optimal accuracy when dividing, for the former, the member into sub-elements, and satisfying, for the latter, a distance between any two consecutive integration points, close to the expected plastic hinge length. On the other hand, using beam-with-hinges elements is computationally more efficient relative to the distributed plasticity, yet with acceptable accuracy provided the user has prior reasonable estimate of the anticipated plastic hinge length. Furthermore, when intrusive performance levels (viz. life safety or collapse) are of concern, concentrated plasticity via beam-with-hinges ensures conservative predicted capacity of investigated bridge systems.

• Journal of English Language & Literature
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• v.55 no.1
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• pp.177-198
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• 2009

How are we approach the fourteenth chapter of Ulysses known as 'The Oxen of the Sun' in this globalized age of hyper-theorization? My paper argues that examining the wide reverberations set off by Derrida's comment in "Ulysses Gramophone"-"Everything has already happened to us with Ulysses"-in relation to the central textual theme of cosmopolitanism may provide a reading that not only pays due respect to the critical legacy of the early structuralist interpretations but equally takes into account the political sensibilities of our time. The neologism 'chaosmopolitanism,'in fact, serves as that very critical measure designed to bridge the gap separating the long tradition of Western Eurocentric discourse on cosmopolitanism on the one hand and the geopolitical background conditioning its discursive possibility, namely, the chaotic condition of international colonialism on the other, whose exemplary, and exemplarily creative, fusion bears none other name than Ulysses. But the idea of chaosmopolitanism gains its conceptual leverage on yet another, no less pivotal register, for, just as with Derrida's first-person plural pronoun, the trope leads us to reflect on our own situatedness in the East Asian region in light of Joyce's unabashedly universalist vision, whose over-arching textual purview nonetheless leaves the space called the Far East in the singular position of virtual exclusion. What does it then mean to enjoy Joyce's "chaffering allincluding most farraginous chronicle" in light of our East Asian perspective? To this second question, my inquiry turns to the dual theme of enjoyment and debt as they are problematized by Stephen Dedalus' telegram to Mulligan, which reads, "the sentimentalist is he who would enjoy without incurring the immense debtorship for a thing done." Itself a quotation from George Meredith's novel The Ordeal of Richard Feverel, the transcribed message invites us to reconsider the scrupulous endeavor underwriting Joyce's signatory gusto, but at the same time forcing us to confront and reassess our own debt to the problematic heritage known as Western literature or, to borrow Derrida's expression, Abrahamic language.

• Geomechanics and Engineering
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• v.35 no.4
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• pp.395-409
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• 2023

Long-span suspension bridges have tunnel anchor systems to maintain stable cables. More investigations are required to determine how closely tunnel excavation beneath the tunnel anchor impacts the stability of the tunnel anchor. In order to investigate the impact of the adjacent tunnel's excavation on the stability of the tunnel anchor, a large-span suspension bridge tunnel anchor is utilised as an example in a three-dimensional numerical simulation approach. In order to explore the deformation control mechanism, orthogonal tests are employed to pinpoint the major impacting elements. The construction of an advanced pipe shed, strengthening the primary support. Moreover, according to the findings the grouting reinforcement of the surrounding rock, have a significant control effect on the settlement of the tunnel vault and plug body. However, reducing the lag distance of the secondary lining does not have such big influence. The greatest way to control tunnel vault settling is to use the grout reinforcement, which increases the bearing capacity and strength of the surrounding rock. This greatly minimizes the size of the tunnel excavation disturbance area. Advanced pipe shed can not only increase the surrounding rock's bearing capacity at the pipe shed, but can also prevent the tunnel vault from connecting with the disturbance area at the bottom of the anchorage tunnel, reduce the range of shear failure area outside the anchorage tunnel, and have the best impact on the plug body's settlement control.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.628-638
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• 2023

Maritime Autonomous Surface ships(MASS) are gradually gaining importance. Until fully autonomous ships are developed, they will likely be controlled by remote operators who are based in a Remote Operations Center. However, there is currently no internationally or domestically established licensing for them. This issue can potentially pose a risk to navigation safety due to operations being handled by unqualified remote operators. We conducted a literature review and proposed criteria for the adoption of a licensing system for remote operators. We have futher offered alternatives to integrate this license into the existing officer licensing system, and analyzed them using Analytic Hierarchy Process(AHP). Subsequently,, theprimary need to enact legislation for remote operators is observed. The most preferred approach is to include the occupation of a remote operator in the Ship Officer Act, Article 4: Occupational Categories and Class of Licenses. Therefore, it would be logical for the organizational structure of the Remote Operation Center to mirror the traditional Bridge Resource Management. This study will contribute to the efficient training of remote operators and the safe navigation of autonomous ships with a focus on human resource management.

• International Journal of Computer Science & Network Security
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• v.23 no.12
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• pp.27-80
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• 2023

Nowadays usage of different applications of identity management IDM demands prime attention to clarify which is more efficient regarding preserve privacy as well as security to perform different operations concerning digital identity. Those operations represent the available interactions with identity during its lifecycle in the digital world e.g., create, update, delete, verify and so on. With the rapid growth in technology, this field has been evolving with a number of IDM models being proposed to ensure that identity lifecycle and face some significant issues. However, the control and ownership of data remines in the hand of identity service providers for central and federated approaches unlike in the self-sovereign identity management SSIM approach. SSIM is the recent IDM model were introduced to solve the issue regarding ownership of identity and storing the associated data of it. Thus, SSIM aims to grant the individual's ability to govern their identities without intervening administrative authorities or approval of any authority. Recently, we noticed that numerous IDM solutions enable individuals to own and control their identities in order to adapt with SSIM model. Therefore, we intend to make comparative study as much of these solutions that have proper technical documentation, reports, or whitepapers as well as provide an overview of IDM models. We will point out the existing research gaps and how this study will bridge it. Finally, the study will propose a technical enhancement, everKEY solution, to address some significant drawbacks in current SSIM solutions.