• Geomechanics and Engineering
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• v.9 no.6
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• pp.775-791
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• 2015

Due to the extension of communication ways (metro, highways, railways), hence, to improve traffic flow imposes often the difficult crossing that generally drive to the construction of underground works (tunnel, water conveyance tunnel...) plays a major role in the redevelopment of urban areas. This study is focused on the assessment of the interaction response of parallel tunnels, so this study uses the results from the simulation of two tunnels to illustrate a few observations that may aid in practical designs. In this article, simultaneous drilling of highway's twin tunnels is simulated by means of Finite Element Method (FEM) implemented in Plaxis program. So the treated subject appears in a setting of geotechnical where one can be to construct several tunnels sometimes in a ground of weak mechanical characteristics. The objective of this study is to simulate numerically the interaction effects caused by construction of two parallels tunnels. This is an important factor in the study of the total answer of the problem interaction between parallels underground works. The importance of the effects transmitted is function of several parameters as the type of the works, and the mechanical characteristics (tunnel size, depth, and the relative position between two tunnels, lining thickness...). This article describes numerical analyses of two parallels tunnels interaction. This study will be applied to a real case of a section tunnel T4 of the highway East-West (Algeria); the study presented below comprises a series of numerical simulations of two tunnels using the computer program Plaxis which is used in the analyses is based on Finite Element Method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.465-469
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• 2019

In this paper, the design of BLDC (brushless direct current) motors based on torque and back-EMF equations was carried out to assess the application of the motor in concrete vibrators. The air gap flux density of the motor is an important parameter because the length of the motor and the size of the diameter are given. The air gap magnetic flux density was calculated through a simplified magnetic circuit, and basic design of the shape and dimensions of the motor were then determined by carrying out experiments based on torque, back-EMF, and air magnetic flux density equations. After setting the outer and inner diameters, stack lengths, and rated speed of the motor, a detailed design was performed by simulations using the finite element method by designating the diameter and thickness of the motor as the key parameters. The final design to satisfy the target torque and the lowest THD (Total Harmonic Distortion) was carried out along with a simulation.

• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1738-1748
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• 2019

Previous research has shown that the inclined condition has an impact on the natural circulation (natural circulation) mode operation of Floating Nuclear Power Plant (FNPP) mounted on the movable marine platform. Due to its compact structure, small volume, strong maneuverability, the Integral Pressurized Water Reactor (IPWR) is adopted as marine reactor in general. The OTSGs of IPWR are symmetrically arranged in the annular region between the reactor vessel and core support barrel in this paper. Therefore, many parallel natural circulation loops are built between the core and the OTSGs primary side when the main pump is stopped. and the inclined condition would lead to discrepancies of the natural circulation drive head among the OTSGs in different locations. In addition, the flow rate and temperature nonuniform distribution of the core caused by inclined condition are coupled with the thermal hydraulics parameters maldistribution caused by OTSG group operating mode on low power operation. By means of the RELAP5 codes were modified by adding module calculating the effect of inclined, heaving and rolling condition, the simulation model of IPWR in inclined condition was built. Using the models developed, the influences on natural circulation operation by inclined angle and OTSG position, the transitions between forced circulation (forced circulation) and natural circulation and the effect on natural circulation operation by different OTSG grouping situations in inclined condition were analyzed. It was observed that a larger inclined angle results the temperature of the core outlet is too high and the OTSG superheat steam is insufficient in natural circulation mode operation. In general, the inclined angle is smaller unless the hull is destroyed seriously or the platform overturn in the ocean. In consequence, the results indicated that the IPWR in the movable marine platform in natural circulation mode operation is safety. Selecting an appropriate average temperature setting value or operating the uplifted OTSG group individually is able to reduce the influence on natural circulation flow of IPWR by inclined condition.

• Journal of IKEEE
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• v.23 no.1
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• pp.254-260
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• 2019

The failure rate of bidirectional dc-to-dc converter is predicted through the failure mode and effect analysis (FMEA) and the fault-tree analysis (FTA) considering the operational risk. In order to increase the driving voltage of the electric vehicle efficiently, the bidirectional converter is attached to the front of the inverter. It has a boost mode for discharging battery power to the dc-link capacitor and a buck mode for charging the regenerative power to the battery. Based on the results of the FMEA considering the operating characteristics of the bidirectional converter, the fault-tree is designed considering the risk of the converter. After setting the design parameters for the MCU for the electric vehicle, we analyze the failure rate of the capacitor due to the output voltage ripple and the inductor component failure rate due to the inductor current ripple. In addition, we obtain the failure rate of major parts according to operating temperature using MIL-HDBK-217F. Finally, the failure rate and the mean time between failures (MTBF) of the converter are predicted by reflecting the part failure rate to the basic event of the fault-tree.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3708-3728
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• 2021

Indian herbal plants are used in agriculture and in the food, cosmetics, and pharmaceutical industries. Laboratory-based tests are routinely used to identify and classify similar herb species by analyzing their internal cell structures. In this paper, we have applied computer vision techniques to do the same. The original leaf image was preprocessed using the Chan-Vese active contour segmentation algorithm to efface the background from the image by setting the contraction bias as (v) -1 and smoothing factor (µ) as 0.5, and bringing the initial contour close to the image boundary. Thereafter the segmented grayscale image was fed to a leaky capacitance fired neuron model (LCFN), which differentiates between similar herbs by combining different groups of pixels in the leaf image. The LFCN's decay constant (f), decay constant (g) and threshold (h) parameters were empirically assigned as 0.7, 0.6 and h=18 to generate the 1D feature vector. The LCFN time sequence identified the internal leaf structure at different iterations. Our proposed framework was tested against newly collected herbal species of natural images, geometrically variant images in terms of size, orientation and position. The 1D sequence and shape features of aloe, betel, Indian borage, bittergourd, grape, insulin herb, guava, mango, nilavembu, nithiyakalyani, sweet basil and pomegranate were fed into the 5-fold Bayesian regularization neural network (BRNN), K-nearest neighbors (KNN), support vector machine (SVM), and ensemble classifier to obtain the highest classification accuracy of 91.19%.

• Journal of the FoodService Safety
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• v.2 no.2
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• pp.67-77
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• 2021

Concerns regarding work and food safety in foodservice operations are growing. The purpose of the study is to suggest guidelines for designing foodservice facilities, including school foodservices and Korean restaurants. A case of a franchise restaurant specializing in a Korean food item, Seolleongtang, was used to explain the facility design. The contents of the manual included ways to determine space allocation, calculate the application of utilities and the diameters of supply utility pipelines, and suggestions on how to decide on air conditioning equipment. The standards of the American Gas Association and the Japan Foodservice Equipment Association (JFEA) were applied to design the restaurant space. The JFEA standards and knowledge based on experience and statistics were applied to calculate the usage of utilities like fuel and water. The standards of JFEA and the Society of Heating, Air-Conditioning, and Sanitary Engineers of Japan were applied to calculate the diameters of the water supply and drainage pipelines. For the setting of the heating, ventilation, and air conditioning systems, three ways to carry out the calculation of effective ventilation were explained, as well as options to dicide the standard parameters of the duct and ventilation fans. This manual can contribute to the design of effective and efficient foodservice facilities and help secure the work safety of foodservice employees thereby ensuring food safety.

• Journal of Environmental Health Sciences
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• v.48 no.2
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• pp.123-129
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• 2022

Background: The Environmental Health Action Program was a national project carried out from 2012~2021. It was aimed at developing public technologies to protect people's health from various environmental hazards. Objectives: One of the final goals of the project was "creating health benefits worth more than 179.2 billion won by reducing the environmental burden of disease." This study aims to evaluate whether the program sufficiently achieved the planned benefits. Methods: In order to secure consistency in evaluation, we applied the same equation used in the goal-setting process. It is comprised of six parameters to estimate the benefit: 1. The amount of medical expenses for environmental diseases; 2. The attributable proportion of environmental risk factors' 3. The rate of reduction in medical expenses for environmental diseases; 4. R&D project contribution; 5. The proportion of successful policy reflection; and 6. The contributions of the project. The corresponding variables were estimated at the end of the project, and the health benefits of the project were recalculated using the newly estimated variables. Results: It was estimated that a total of 195 billion won in health benefits occurred or will occur from 2015 to 2026. The main contributors for achieving the target were an increase in medical expenses for environmental diseases, a high score in the R&D project contribution, and the proportion of successful policy reflection. Conclusions: Technically, the equation used in the project is about medical expenses for environmental diseases rather than about the environmental burden of disease. There are several benefits of using the environmental burden of disease in the evaluation of public health policies. In further studies, developing a policy evaluation framework using indicators such as population attributable fraction would be needed.

• Journal of IKEEE
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• v.26 no.4
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• pp.577-583
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• 2022

Verilog-HDL-based modeling can be performed to confirm the fast operation characteristics after setting the design parameters of each block considering the stability of the system by performing linear phase-domain modeling on the phase-locked loop. This paper proposed Verilog-HDL modeling including DCO noise and DTC nonlinear characteristic. After completing the modeling, the time-domain transient simulation can be performed to check the feasibility and the functionality of the proposed PLL system, then the phase noise result from the system design based on the functional model can be verified comparing with the ideal phase noise graph. As a result of the comparison of simulation time (6 us), the Verilog-HDL-based modeling method (1.43 second) showed 484 times faster than the analog transistor level design (692 second) implemented by TSMC 0.18-㎛.

• Journal of the Korea Society for Simulation
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• v.32 no.1
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• pp.13-21
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• 2023

This paper proposes a method of automatically generating a model through a machine learning technique by setting a hypothetical model in the form of a gray box or black box with unknown parameters, when the big data of the actual system is given. We implements the proposed framework and conducts experiments to find an appropriate model among various hypothesis models and compares the cost and fitness of them. As a result we find that the proposed framework works well with continuous systems that could be modeled with ordinary differential equation. This technique is expected to be used well for the purpose of automatically updating the consistency of the digital twin model or predicting the output for new inputs using recently generated big data.

• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.33-40
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• 2009

Edge detection is very significant in low level image processing. However, majority edge detection methods are not only effective enough cause of the noise points' influence, even not flexible enough to different input images. In order to sort these problems, in this paper an algorithm is presented that has an extra noise reduction stage at first, and then automatically selects the both thresholds depending on gradient amplitude histogram and intra class minimum variance. Using this algorithm, can fade out almost all of the sensitive noise points, and calculate the propose thresholds for different images without setting up the practical parameters artificially, and then choose edge pixels by fuzzy algorithm. In finally, get the better result than the former Canny algorithm.