• International Journal of Computer Science & Network Security
• /
• v.21 no.9
• /
• pp.11-18
• /
• 2021

The Proportional Integral Derivative (PID) controller is the most popular industrial controller and more than 90% process industries use this controller. During the past 50 years, numerous good tuning methods have been proposed for Single Input Single Output Systems. However, design of PI/PID controllers for multivariable processes is a challenge for the researchers. A comparative study of three PID controllers design methods has been carried-out. These methods include the DS (Direct Synthesis) method, IMC (Internal model Control) method and ETF (Effective Transfer Function) method. MIMO PID controllers are designed for a number of 2×2, 3×3 and 4×4 process models with multiple delays. The performance of the three methods has been evaluated through simulation studies in Matlab/Simulink environment. After extensive simulation studies, it is found that the Effective Transfer Function (ETF) Method produces better output responses among two methods. In this work, only decentralized methods of PID controllers have been studied and investigated.

• International Journal of Computer Science & Network Security
• /
• v.22 no.6
• /
• pp.127-130
• /
• 2022

The number of published journals, conferences, and research papers in computer science is increasing rapidly, which has led to a challenge in coming up with new and unique ideas for research. To alleviate the issue, this paper uses artificial neural networks (ANNs) to generate new computer science research ideas. It does so by using a dataset collected from IEEE published journals and conferences to train an ANN model. The results reveal that the model has a 14% success rate in generating usable ideas. The outcome of this paper has implications for helping both new and experienced researchers come up with novel research topics.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.11
• /
• pp.3493-3506
• /
• 2022

In the field of scene segmentation, the precise segmentation of object boundaries in sports movement scene images is a great challenge. The geometric information and spatial information of the image are very important, but in many models, they are usually easy to be lost, which has a big influence on the performance of the model. To alleviate this problem, a parallel dense dilated convolution merging Network (termed PDDCM-Net) was proposed. The proposed PDDCMNet consists of a feature extractor, parallel dilated convolutions, and dense dilated convolutions merged with different dilation rates. We utilize different combinations of dilated convolutions that expand the receptive field of the model with fewer parameters than other advanced methods. Importantly, PDDCM-Net fuses both low-level and high-level information, in effect alleviating the problem of accurately segmenting the edge of the object and positioning the object position accurately. Experimental results validate that the proposed PDDCM-Net achieves a great improvement compared to several representative models on the COCO-Stuff data set.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.3
• /
• pp.86-91
• /
• 2022

The mechanical structures mounted on vehicles or aircrafts are subject to random accelerations, such as earthquakes, at the base, and their responses have been calculated through spectrum analysis. However, this method poses a challenge during the synthesis of the responses owing to the loss of the vibration phase. It is necessary to evaluate the time history results to obtain the exact responses; therefore, an efficient technique is proposed to solve this issue. The present technique involves constructing a superelement using the sub-structuring method and finding solutions for this superelement. The finite element model (FEM) was substituted by a superelement, which was simplified into one element with selected nodes. Comparing the numerical results of the superelement with the time history responses for the original finite element model, the two solutions agree well despite the fact that the computation time of the proposed technique has been greatly shortened.

• Journal of the Korean Society of Visualization
• /
• v.21 no.2
• /
• pp.8-13
• /
• 2023

The primary challenge in improving fuel efficiency and reducing air pollution for commercial vehicles is reducing their aerodynamic drag. Various flow control devices, such as cab-roof fairing, gap fairing, cab extender, and side skirt have been introduced to reduce drag, however, the drag reduction effect and applicability are different depending on each commercial vehicle model. To evaluate the fuel consumption of heavy vehicles, a comprehensive research approach, including drag force measurement, flow field analysis is required. This study investigated the effect of a cab extender, which installed rear region of cab, on a drag coefficient of commercial vehicle through wind tunnel experiments and CFD. The results showed that the cab extender significantly modified the flow structure around the vehicle, leading to 8.2% reduction in drag coefficient compared to the original vehicle model. These results would provide practical application for enhancing the aerodynamic performance and fuel efficiency of heavy vehicle.

• International conference on construction engineering and project management
• /
• 2015.10a
• /
• pp.544-548
• /
• 2015

As urbanization increases in UAE, the demand for housing and infrastructures also grows. The challenge is to continue to build but in a different way considering more energy-efficient sustainable buildings. Producing a sustainable design is highly dependent upon effective participation among the diverse parties involved. In the construction industry in the UAE, these parties are fragmented due to the multistage nature of construction projects and multidisciplinary participants, particularly during the design stage. The decisions made during this stage have an extensive impact on subsequent stages of a project's life cycle. Having a sustainability expert during the design stage is important and the awareness of sustainability requirements by all design participants is of equal importance. In this research, recent advances in information technology are used to develop an information model that will improve the sustainability of building during the design stage. An information framework for storing design information and sustainability performance criteria is developed, allowing design participants to collaborate in an integrated environment. This research is expected to help designers produce sustainable designs for building projects.

• International Journal of Advanced Culture Technology
• /
• v.12 no.2
• /
• pp.386-401
• /
• 2024

The study introduces and validates a model of post-traumatic growth among parents of children with special needs. The model incorporates cognitive processes, coping strategies, and sociocultural factors as intra-personal variables. The statistical analysis unveiled significant pathways that connect the factors, explaining 71% of the variance associated with post-traumatic growth. The study highlighted intentional reflection and robust decentralization skills as crucial factors that predict post-traumatic growth. Deliberate rumination functioned as a mediating factor, reducing the impact of trauma and facilitating post-traumatic growth, while social support played a crucial role in initiating purposeful rumination. The study findings indicate that the effect of self-disclosure on post-traumatic growth is not direct but rather indirect, as it is mediated by its influence on social support and deliberate rumination. The study underscores the significance of examining particular characteristics of social support networks and suggests integrating additional variables for future research, such as gender, types of traumatic events, and the age of children with disabilities.

• Structural Engineering and Mechanics
• /
• v.89 no.4
• /
• pp.399-409
• /
• 2024

Assessment of existing concrete bridges is a challenge for owners. It has greater economic impact when compared to designing new bridges. When using conventional linear analyses, judgment of the engineer is required to understand the behavior of redundant structures after the first element in the structural system reaches its ultimate capacity. The alternative is to use a predictive tool such as advanced nonlinear finite element analyses (ANFEA) to assess the overall structural behavior. This paper proposes a new reliability framework for the assessment of existing bridge structures using ANFEA. A general framework defined in previous works, accounting for material uncertainties and concrete model performance, is adapted to the context of the assessment of existing bridges. A "shifted" reliability problem is defined under the assumption of quasi-deterministic dead load effects. The overall exercise is viewed as a progressive pushover analysis up to structural failure, where the actual safety index is compared at each event to a target reliability index.

• Journal of the Korean Society of Earth Science Education
• /
• v.12 no.1
• /
• pp.64-81
• /
• 2019

The purpose of this study is to analyze elementary science gifted students' characteristics of the thinking in the problem solving process through a MEA(Model Eliciting Activity)activity. The subjects of this study are 40 elementary science gifted students who passed the first screen for the admission to the science gifted education institute in P university in 2018. The MEA activity was 'Coffee cup challenge', which is to find the best way to place cup side and bottom to save paper in a given material. Three drawings from each student and explanations of each drawing through out the design process were collected as the main data source. The data were analyzed by statistically (correlation coefficient) and qualitatively to find the relationship between; 1) the intuitive thinking and visual representation and 2) analytical thinking ability and communication skills that reflect MEA activities. In conclusion, first, intuitive thinking plays an important role in the ability of visual representation through pictures and the whole problem solving process. Second, the analytical thinking and elaboration process which are reflected through reflection on the arrangement of the drawings have a great influence on the communication skills. Therefore, this study investigated that MEA activities are useful activities to stimulate both intuitive and analytical thinking in elementary science gifted students, and to develop communication ability, by organizing their own ideas and providing learning opportunities for various solutions.

• Journal of Applied Reliability
• /
• v.14 no.4
• /
• pp.225-229
• /
• 2014

A one-shot device is defined as a product, system, weapon, or equipment that can be used only once. After use, the device is destroyed or must undergo extensive rebuild. Determining the reliability of a one-shot device poses a unique challenge to the manufacturers and users due to the destructive nature and costs of the testing. This paper presents a reliability growth prediction for a one-shot system. It is assumed that 1) test duration is discrete(i.e. trials or rounds); 2) trials are statistically independent; 3) the number of failures for a given system configuration is distributed according to a binomial distribution; and 4) the cumulative expected number of failures through any sequence of configurations is given by AMSAA model. When the system development is represented by three configurations and the number of trials and failures during configurations are given, the AMSAA model parameters and reliability at configuration 3 are estimated by using a reliability growth analysis software. Further, if the reliability growth predictions do not meet the target reliability, the sample size of an additional test is determined for achieving the target reliability.