• International Journal of Computer Science & Network Security
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• 제23권11호
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• pp.83-92
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• 2023

The majority of product users rely on the reviews that are posted on the appropriate website. Both users and the product's manufacturer could benefit from these reviews. Daily, thousands of reviews are submitted; how is it possible to read them all? Sentiment analysis has become a critical field of research as posting reviews become more and more common. Machine learning techniques that are supervised, unsupervised, and semi-supervised have worked very hard to harvest this data. The complicated and technological area of feature engineering falls within machine learning. Using deep learning, this tedious process may be completed automatically. Numerous studies have been conducted on deep learning models like LSTM, CNN, RNN, and GRU. Each model has employed a certain type of data, such as CNN for pictures and LSTM for language translation, etc. According to experimental results utilizing a publicly accessible dataset with reviews for all of the models, both positive and negative, and CNN, the best model for the dataset was identified in comparison to the other models, with an accuracy rate of 81%.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.57-66
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• 2022

Claims and disputes are major causes of cost and schedule overruns in the construction business. In order to manage claims and disputes effectively, it is necessary to analyze various types of contract documents punctually and accurately. Since volume of such documents is so vast, analyzing them in a timely manner is practically very challenging. Recently developed approaches such as artificial intelligence (AI), machine learning algorithms, and natural language processing (NLP) have been applied to various topics in the field of construction contract and claim management. Based on the systematic literature review, this paper analyzed the goals, methodologies, and application results of such approaches. AI methods applied to construction contract management are classified into several categories. This study identified possibilities and limitations of the application of such approaches. This study contributes to providing the directions for how such approaches should be applied to contract management for future studies, which will eventually lead to more effective management of claims and disputes.

• Smart Structures and Systems
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• 제29권1호
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• pp.141-151
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• 2022

In recent years, the industry and research communities have focused on developing autonomous crack inspection approaches, which mainly include image acquisition and crack detection. In these approaches, mobile devices such as cameras, drones or smartphones are utilized as sensing platforms to acquire structural images, and the deep learning (DL)-based methods are being developed as important crack detection approaches. However, the process of image acquisition and collection is time-consuming, which delays the inspection. Also, the present mobile devices such as smartphones can be not only a sensing platform but also a computing platform that can be embedded with deep neural networks (DNNs) to conduct on-site crack detection. Due to the limited computing resources of mobile devices, the size of the DNNs should be reduced to improve the computational efficiency. In this study, an architecture called pruned crack recognition network (PCR-Net) was developed for the detection of structural cracks. A dataset containing 11000 images was established based on the raw images from bridge inspections. A pruning method was introduced to reduce the size of the base architecture for the optimization of the model size. Comparative studies were conducted with image processing techniques (IPTs) and other DNNs for the evaluation of the performance of the proposed PCR-Net. Furthermore, a modularly designed framework that integrated the PCR-Net was developed to realize a DL-based crack detection application for smartphones. Finally, on-site crack detection experiments were carried out to validate the performance of the developed system of smartphone-based detection of structural cracks.

• 한국정보전자통신기술학회논문지
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• 제10권4호
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• pp.257-267
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• 2017

압축센싱(Compressed Sensing)은 선형 역문제(inverse problem)를 다루고 있으며, 그 이론적 연구결과는 관련 분야에 많은 영향을 주어 놀랄 만한 연구성과를 발표하였다. 그러나 압축센싱을 실제 환경에 적용하기 위해서는 두 가지 중요한 문제가 남아 있다. 하나는 실시간에 가까운 복원 성능이 보장되어야 하며, 다른 하나는 신호가 희소성을 갖도록 전처리가 가능해야 한다는 점이다. 이에 대한 문제들을 해결하고자 딥러닝(deep learning) 기술을 활용한 압축센싱 신호 복원방법이 최근에 등장하였다. 본 논문에서는 딥러닝 기반의 압축센싱 신호 복원방법을 고찰하고 최신 연구결과를 비교 분석하고자 한다. 관련 연구결과에서는 실시간에 가까운 복원 시간에 도달하였으며, 기존 복원방법 대비 더 우수한 복원 성능을 보여 주었다. 최근 연구에서 보여준 딥러닝을 활용한 압축센싱 신호 복원방법은 압축센싱의 활용가치를 더욱 높일 뿐만 아니라 신호처리와 통신분야에서 크게 활용될 수 있을 것으로 기대된다.

• 비교교육연구
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• 제27권3호
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• pp.101-127
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• 2017

본 연구의 목적은 글로벌 교육의제들 속에서 드러나고 있는 학습 및 학습 성과에 대한 논의가 어떻게 변해 왔는지를 비판적으로 분석하고 이를 바탕으로 국제교육개발협력이 나아갈 방향성과 시사점을 얻는데 있다. 이를 위해 국제교육계의 3대 글로벌교육회의라 일컬어지는 1990년 좀티엔 세계교육회의, 2000년 다카르 세계교육포럼, 그리고 2015년 인천 세계교육포럼으로 줄기를 잇는 국제 선언을 분석의 축으로 삼고자 한다. 여기서 다루어진 핵심 내용과 방향이 무엇이고 학습을 다루는 목적과 위상, 그리고 한계를 고찰하였다. 연구결과 글로벌교육의제에서 학습 담론이 거의 생략되어왔고, SDGs 교육의제 하에서의 학습 담론도 개념의 모호성으로 인해서 개발도상국에서 제대로 수용되지 못하는 문제가 드러났다. 또한 '학습성과'를 '학습평가'로 등식화하면서 양질의 교육을 보장하기 위해서 '평가'에만 몰입하는 방향이 나타나는 모순적 상황이 한계로 드러났다. 이에 앞으로의 국제교육개발협력사업은 첫째, 선진국의 교육 시스템 및 기존 지식 제공 방식이 아니라 탈식민주의 관점에서 그리고 학습자 중심주의의 교육적 접근을 통하여 추진되어야 한다. 둘째, 일회성의 국제교육개발협력사업이 아닌 개발도상국 학습자의 성장을 지속가능하도록 지원하는 방식으로 전체 틀이 다시 설계될 필요가 있다. 그리고 셋째, 앞으로의 교육개발사업은 그 발굴단계에서 하드웨어가 아니라 학습자의 학습 과정과 성취를 고려한 소프트웨어 개발 중심으로 추진될 필요가 있다. 이제 학습 주의와 교육학의 전문적 지식을 사업 발굴 단계 및 진행과정에 연계하여 국제교육개발협력에서 '교육적' 의미를 높일 수 있는 방향이 무엇인지 깊은 성찰이 필요하다.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.374-388
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• 2022

Cloud computing has been one of the most critical technology in the last few decades. It has been invented for several purposes as an example meeting the user requirements and is to satisfy the needs of the user in simple ways. Since cloud computing has been invented, it had followed the traditional approaches in elasticity, which is the key characteristic of cloud computing. Elasticity is that feature in cloud computing which is seeking to meet the needs of the user's with no interruption at run time. There are traditional approaches to do elasticity which have been conducted for several years and have been done with different modelling of mathematical. Even though mathematical modellings have done a forward step in meeting the user's needs, there is still a lack in the optimisation of elasticity. To optimise the elasticity in the cloud, it could be better to benefit of Machine Learning algorithms to predict upcoming workloads and assign them to the scheduling algorithm which would achieve an excellent provision of the cloud services and would improve the Quality of Service (QoS) and save power consumption. Therefore, this paper aims to investigate the use of machine learning techniques in order to predict the workload of Physical Hosts (PH) on the cloud and their energy consumption. The environment of the cloud will be the school of computing cloud testbed (SoC) which will host the experiments. The experiments will take on real applications with different behaviours, by changing workloads over time. The results of the experiments demonstrate that our machine learning techniques used in scheduling algorithm is able to predict the workload of physical hosts (CPU utilisation) and that would contribute to reducing power consumption by scheduling the upcoming virtual machines to the lowest CPU utilisation in the environment of physical hosts. Additionally, there are a number of tools, which are used and explored in this paper, such as the WEKA tool to train the real data to explore Machine learning algorithms and the Zabbix tool to monitor the power consumption before and after scheduling the virtual machines to physical hosts. Moreover, the methodology of the paper is the agile approach that helps us in achieving our solution and managing our paper effectively.

• International Journal of Computer Science & Network Security
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• 제21권9호
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• pp.155-162
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• 2021

The expansion of the world wide web has led to a huge amount of user generated content over different forums and social media platforms, these rich data resources offer the opportunity to reflect, and track changing public sentiments and help to develop proactive reactions strategies for decision and policy makers. Analysis of public emotions and opinions towards events and sentimental trends can help to address unforeseen areas of public concerns. The need of developing systems to analyze these sentiments and the topics behind them has emerged tremendously. While most existing works reported in the literature have been carried out in English, this paper, in contrast, aims to review recent research works in Arabic language in the field of thematic sentiment analysis and which techniques they have utilized to accomplish this task. The findings show that the prevailing techniques in Arabic topic-based sentiment analysis are based on traditional approaches and machine learning methods. In addition, it has been found that considerably limited recent studies have utilized deep learning approaches to build high performance models.

• 한국인터넷방송통신학회논문지
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• 제21권3호
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• pp.175-181
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• 2021

본 논문은 단기 에너지 사용량 예측을 위해 인공지능 기반의 접근법에 대해 분석한다. 본 논문에서는 단기 에너지 사용량 예측 기술에 자주 활용되는 지도학습 알고리즘의 한계를 개선하기 위해 강화학습 알고리즘을 활용한다. 지도학습 알고리즘 기반의 접근법은 충분한 성능을 위해 에너지 사용량 데이터뿐만 아니라 contextual information이 필요하여 높은 복잡성을 가진다. 데이터와 학습모델의 복잡성을 개선하기 위해 다중 에이전트 기반의 심층 강화학습 알고리즘을 제안하여 에너지 사용량 데이터로만 에너지 사용량을 예측한다. 공개된 에너지 사용량 데이터를 통해 시뮬레이션을 진행하여 제안한 에너지 사용량 예측 기법의 성능을 확인한다. 제안한 기법은 이상점의 특징을 가지는 데이터를 제외하고 실제값과 유사한 값을 예측하는 것을 보여준다.

• Smart Structures and Systems
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• 제29권2호
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• pp.321-336
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• 2022

Model uncertainty is a key factor that could influence the accuracy and reliability of numerical model-based analysis. It is necessary to acquire an appropriate updating approach which could search and determine the realistic model parameter values from measurements. In this paper, the Bayesian model updating theory combined with the transitional Markov chain Monte Carlo (TMCMC) method and K-means cluster analysis is utilized in the updating of the structural model parameters. Kriging and polynomial chaos expansion (PCE) are employed to generate surrogate models to reduce the computational burden in TMCMC. The selected updating approaches are applied to three structural examples with different complexity, including a two-storey frame, a ten-storey frame, and the national stadium model. These models stand for the low-dimensional linear model, the high-dimensional linear model, and the nonlinear model, respectively. The performances of updating in these three models are assessed in terms of the prediction uncertainty, numerical efforts, and prior information. This study also investigates the updating scenarios using the analytical approach and surrogate models. The uncertainty quantification in the Bayesian approach is further discussed to verify the validity and accuracy of the surrogate models. Finally, the advantages and limitations of the surrogate model-based updating approaches are discussed for different structural complexity. The possibility of utilizing the boosting algorithm as an ensemble learning method for improving the surrogate models is also presented.

• 천문학회보
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• 제45권1호
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• pp.50.2-50.2
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• 2020

The dark matter (DM) only simulations have been exploited to study e.g. the large scale structures and properties of a halo. In a baryon side, the high-resolution hydrodynamic simulation such as IllustrisTNG has helped extend the physics of gas along with stars and DM. However, the expansive computational cost of hydrodynamic simulations limits the size of a simulated universe whereas DM-only simulations can generate the universe of the cosmological horizon size approximately. I will introduce a pipeline to estimate baryonic properties of a galaxy inside a dark matter (DM) halo in DM-only simulations using a machine trained on high-resolution hydrodynamic simulations. An extremely randomized tree (ERT) algorithm is used together with multiple novel improvements such as a refined error function in machine training and two-stage learning. By applying our machine to the DM-only simulation of a large volume, I then validate the pipeline that rapidly generates a galaxy catalog from a DM halo catalog using the correlations the machine found in hydrodynamic simulations. I will discuss the benefits that machine-based approaches like this entail, as well as suggestions to raise the scientific potential of such approaches.