• Computers and Concrete
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• v.24 no.3
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• pp.207-222
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• 2019

This paper has presented an effective and accurate meso-scale finite element model for simulating the fracture process of concrete under compression-shear loading. In the proposed model, concrete is parted into four important phases: aggregates, cement matrix, interfacial transition zone (ITZ), and the initial defects. Aggregate particles were modelled as randomly distributed polygons with a varying size according to the sieve curve developed by Fuller and Thompson. With regard to initial defects, only voids are considered. Cohesive elements with zero thickness are inserted into the initial mesh of cement matrix and along the interface between aggregate and cement matrix to simulate the cracking process of concrete. The constitutive model provided by ABAQUS is modified based on Wang's experiment and used to describe the failure behaviour of cohesive elements. User defined programs for aggregate delivery, cohesive element insertion and modified facture constitutive model are developed based on Python language, and embedded into the commercial FEM package ABAQUS. The effectiveness and accuracy of the proposed model are firstly identified by comparing the numerical results with the experimental ones, and then it is used to investigate the effect of meso-structure on the macro behavior of concrete. The shear strength of concrete under different pressures is also involved in this study, which could provide a reference for the macroscopic simulation of concrete component under shear force.

• Safety and Health at Work
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• v.10 no.3
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• pp.321-326
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• 2019

Background: Performing cognitive tasks and muscular fatigue have been shown to increase muscle activity of the lower extremity during quiet standing. A common intervention to reduce muscular fatigue is to provide a softer shoe-surface interface. However, little is known regarding how muscle activity is affected by softer shoe-surface interfaces during static standing. The purpose of this study was to assess lower extremity muscular activity during erect standing on three different standing surfaces, before and after an acute workload and during cognitive tasks. Methods: Surface electromyography was collected on ankle dorsiflexors and plantarflexors, and knee flexors and extensors of fifteen male participants. Dependent electromyography variables of mean, peak, root mean square, and cocontraction index were calculated and analyzed with a $2{\times}2{\times}3$ within-subject repeated measures analysis of variance. Results: Pre-workload muscle activity did not differ between surfaces and cognitive task conditions. However, greater muscle activity during post-workload balance assessment was found, specifically during the cognitive task. Cognitive task errors did not differ between surface and workload. Conclusions: The cognitive task after workload increased lower extremity muscular activity compared to quite standing, irrespective of the surface condition, suggesting an increased demand was placed on the postural control system as the result of both fatigue and cognitive task.

• International Journal of High-Rise Buildings
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• v.8 no.2
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• pp.101-106
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• 2019

Assessing the energy performance of supertall buildings often does not consider variations in energy consumption due to the change of environmental conditions such as temperature, pressure, and wind speed associated with differing elevations. Some modelers account for these changing conditions by using a conventional temperature lapse rate, but not many studies confirm to the appropriateness of applying it to tall buildings. This paper presents and discusses simulated annual energy consumption results from a 600 m tall skyscraper floor plate located in Dubai, UAE, assessed using ground level weather data, a conventional temperature lapse rate of $6.5^{\circ}C/km$, and more accurate simulated 600 m weather data. A typical office floorplate, with ASHRAE 90.1-2010 standards and systems applied, was evaluated using the EnergyPlus engine through the OpenStudio graphical user interface. The results presented in this paper indicate that by using ground level weather data, energy consumption at the top of the building can be overestimated by upwards of 4%. Furthermore, by only using a lapse rate, heating energy is overestimated by up to 96% due to local weather phenomenon such as temperature inversion, which can only be conveyed using simulated weather data. In addition, sizing and energy consumption of fans, which are dependent both on wind and atmospheric pressure, are not accurately captured using a temperature lapse rate. These results show that that it is important, with the ever increasing construction of supertall buildings, to be able to account for variations in climatic conditions along the height of the building. Adequately modeling these conditions using simulated weather data will help designers and engineers correctly size mechanical systems, potentially decreasing overall building energy consumption, and ensuring that these systems are able to provide the necessary indoor conditions to maintain occupant comfort levels.

• International Journal of Advanced Culture Technology
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• v.8 no.4
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• pp.82-88
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• 2020

With the development of medical care in the 21st century and the rapid development of the 4th industry, electronic devices and household goods taking into account the physical and mental aging of the silver generation have been developed, and apps related to health and health are generally developed and operated. The apps currently used by the silver generation are a form that provides information on diseases by focusing on prevention rather than treatment, such as safety management apps for the elderly living alone and methods for preventing diseases. There are not many apps that provide information on foods that have a direct effect and nutrients in that food, and research on apps that can obtain information about individual foods is insufficient. In this paper, we propose an app that analyzes food factors and provides self-medication for health promotion of the silver generation. This app allows the silver generation to conveniently and easily obtain information such as nutrients, calories, and efficacy of food they need. In addition, this app collects/categorizes healthy food information through a textom solution-based crawling agent, and stores highly relevant words in a data resource. In addition, wide deep learning was applied to enable self-medication recommendations for food. When this technique is applied, the most appropriate healthy food is suggested to people with similar eating patterns and tastes in the same age group, and users can receive recommendations on customized healthy foods that they need before eating. This made it possible to obtain convenient healthy food information through a customized interface for the elderly through a smartphone.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.1
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• pp.163-172
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• 2020

This study is a case study for in-house developed Record Maintenance and Management (RMMS) which is a digital data storage/retrieval system in a GIS-enabled solution. RMMS is designed for reorganizing submitted architectural drawings associated with scanned drawings files & geodatabase, managing metadata/table and geometric features in ArcSDE/Enterprise geodatabase format. The birth of the RMMS was borne out of a necessity for a modernized approach in digital file basis to provide improved customer services for various architectural drawings and associated with geo-spatial and its attribute information. Through a case study for building permit & review practice implemented on an internet-based Electronic Architectural administration Information System (EAIS) at the local governments in Korea, this study is able to derive differences between GIS-enabled RMMS system implemented in the Richmond City and internet-based EAIS system implemented in the local government in Korea. In an effort to be the most effective, it presents meaningful ways of maximizing efficiency in record maintenance & management system derived from the case studies that looked into in ways of a method in RMMS' operation, implementation on GIS platform, mutual interface among various programs with various digital files and finally technical supports and system development /upgrade.

• The Journal of Korean Institute of Next Generation Computing
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• v.14 no.6
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• pp.66-74
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• 2018

Recently, there has been active studies on hand gesture recognition to increase immersion and provide user-friendly interaction in a virtual reality environment. However, most studies require specialized sensors or equipment, or show low recognition rates. This paper proposes a hand gesture recognition method using Deep Learning technology without separate sensors or equipment other than camera to recognize static and dynamic hand gestures. First, a series of hand gesture input images are converted into high-frequency images, then each of the hand gestures RGB images and their high-frequency images is learned through the DenseNet three-dimensional Convolutional Neural Network. Experimental results on 6 static hand gestures and 9 dynamic hand gestures showed an average of 92.6% recognition rate and increased 4.6% compared to previous DenseNet. The 3D defense game was implemented to verify the results of our study, and an average speed of 30 ms of gesture recognition was found to be available as a real-time user interface for virtual reality applications.

• Steel and Composite Structures
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• v.39 no.5
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• pp.529-542
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• 2021

Shear connectors are required to build composite (concrete and steel) beams. They are placed at the interface of concrete and steel to transfer shear and normal forces between two structural components. Such composite beams are sensitive to provide structural integrity when exposed to fire as they loss strength, stiffness, and ductility at elevated temperature. The present study is designed to investigate the shear resistance and the failure modes of the headed stud shear connectors at fire exposure and post-fire exposure. The study includes ordinary concrete and concrete with carbon nanotubes (CNTs) to build composite (concrete-steel) beams with structural steel. Experimental push tests were conducted on composite beams at ambient and elevated temperatures, such as 200, 400 & 600℃. Moreover, push tests were performed on the composite beams after being exposed to 200, 400 & 600℃. Push test results illustrated the reduction of ultimate shear capacity and stiffness of headed stud shear connectors as the temperature increased. Although similar values of ultimate shear were obtained for the headed stud connectors in both ordinary and CNT concrete, the CNT modified concrete reduced the concrete spalling and cracking compared to ordinary concrete and was observed to be effective at temperatures greater than 400℃. All specimens showed a lower shear resistance at fire exposures compared to the corresponding post-fire exposures. Moreover, numerical simulation by Finite Element (FE) analyses were carried out at ambient temperature and at fire conditions. The FE analysis results show a good agreement with the experimental results. In the experimental studies, failure of all specimens occurred due to shear failure of headed stud, which was later validated by FE analyses using ABAQUS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.57-64
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• 2020

Recently, due to the proliferation of IoT sensors, the development of big data and artificial intelligence, time series prediction research on fine dust pollution is actively conducted. However, because the data representing fine dust contamination changes rapidly, traditional time series prediction methods do not provide a level of accuracy that can be used in the field. In this paper, we propose a method that reflects the classification results of environmental conditions through CNN when predicting micro dust contamination using LSTM. Although LSTM and CNN are independent, they are integrated into one network through the interface, so this method is easier to understand than the application LSTM. In the verification experiments of the proposed method using Beijing PM2.5 data, the prediction accuracy and predictive power for the timing of change were consistently improved in various experimental cases.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.313-318
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• 2021

In order to treat a disease, it is necessary to take the medication on time, but many people often violate or forget the time they take the medicine. Applications are emerging to solve these problems using information technology. However, for existing applications, it is difficult to use because it provides only a notification functions, user interface is inconvenient, and photo registration of the medication is impossible. To solve these problems, the study developed a smart medicine management application that allows users to set up their taking routines, check if they are taking them, search hospitals and pharmacies, and attach images of medicines they are taking. Through this appliaction, it is possible to reduce the frequency of forgetting the time taken and to take accurate medication by checking the actual image. It also supports the setting of a taking routine to support multiple medications with different taking cycles. It can also provide information about hospital and pharmacies close to their current location to increase access to hospital and pharmacies.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.513-522
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• 2022

The purpose of this study is to evaluate the accessibility of the Cakewalk TTS-1 for the screen reader users. An evaluation was performed by testing the accessibility of a editing virtual instrument that is a part of MIDI production based on the NCS(National Competency Standards) by using the TTS-1 and the Sense Reader. The results of this study are as follows. The TTS-1 itself can't provide enough accessibility for the screen users to do an above task. But the screen reader users can perform the above tasks if they use extended access functions like Sense Reader's Mouse Pointer function, Position Memory function and MIDI Control Signal function. Even if they use the extended access function, there are functions that is difficult to access. To solve this problem, several suggestions are proposed.