• Journal of Digital Convergence
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• v.17 no.11
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• pp.207-213
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• 2019

The fuel-cut coast-down driving mode is activated when the acceleration pedal is released with transmission gear engaged, and it's a default function for electronic-controlled engine of vehicles. The fuel economy becomes better because fuel injection stops during fuel-cut driving mode. A fuel-cut detection method is suggested in the study and it's based on the speed, acceleration and road gradient data from GPS sensor. It detects fuel-cut driving mode by comparing calculated acceleration and realtime acceleration value. The one is estimated with driving resistance in the condition of fuel-cut driving and the other is from GPS sensor. The detection accuracy is about 80% when the method is verified with road driving data. The result is estimated with 9,600 data set of vehicle speed, acceleration, fuel consumption and road gradient from test driving on the road of 12km during 16 minutes, and the road slope is rather high. It's easy to detect fuel-cut without injector signal obtained by connecting wire. The detection error is from the fact that the variation range of speed, acceleration and road gradient data, used for road resistance force, is larger than the value of fuel consumption data.

• Journal of agricultural medicine and community health
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• v.45 no.4
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• pp.194-207
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• 2020

Purpose: The purpose of this study is to develop and evaluate the curriculum, that was the continuing professional development program, for cultivating physician's competencies in public health. Methods: This study was conducted through in-depth interview and survey in the frame of ADDIE, from 2 May to 30 June in 2019. Participants were 7 physicians by in-depth interview and Respondents were 46 physicians worked in public health by survey. Results: The results were analyzed and described in the frame of ADDIE model. In the stage of Analysis, physician's core competencies in public health was presented to practical education, management of organization and labor force, communication with community, and director' role of public health center in the community as core competencies by in-depth interview. The skill - knowledge-attitude competencies were highest in order in the survey for placing priority (by Borich score) of 29 core competencies. In design stage, the educational objective of curriculum was established, that is to develop the competencies of knowledge, skills, and attitude needed for physician of public health in 21th century. In development and implementation stage, it is important to decide to lecturer, to get in advance educational materials to do the maintenance and management of curriculum. In the stage of evaluation, the educational satisfaction was high on the whole and educational effect was statistically significant. Conclusions: This study was an initial study of Korean doctors, and it aims to pursue competency-based education as a continuing professional development (CPD) beyond continuing medical education (CME) including knowledge, skills, and attitudes.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.439-446
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• 2020

The IMO has adopted emission standards through Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL) that strictly prohibit the use of bunker C oil for vessels. In this study, we have adopted the turret-moored Floating LNG-Bunkering Terminal (FLBT) which is designed to receive the LNG from LNGCs and transfer it to LNG-bunkering shuttles in side-by-side moored condition. Numerical analyses were carried out using the high-order boundary-element method for four vessels at various relative distances. Mean wave drift forces were compared in an operational sea state. A model test was performed in the ocean engineering basin at the Korea Research Institute of Ships & Ocean Engineering (KRISO) to verify the safety of the berthing/unberthing operation. In the model test, a jig was designed to simulate tug boats pushing or pulling the bunkering vessels, so that the friction force of the g operation was not affected. Safety depended on the environmental direction, with more stable operation possible if the heading-control function of FLBT is applied to avoid beam-sea conditions.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.45-56
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• 2021

As the utilization of the underground space is activated, deep excavation of ground has been conducted for the installation of underground structures, the earth retaining wall has widely used to minimize deformation of the excavated ground. In particular, as deep excavation is actively progressing in an urban area where structures are concentrated, methods to minimize the deformation of wall have been devised to prevent damage to the structure adjacent to the wall, and one of these methods is the pre-loading method. This method is a method of suppressing the deformation of wall by actively applying a load on the strut to be installed in wall, and research on this method has been conducted recently. However, although related studies have been actively conducted, the management standard for the pre-loading of bracing has not been clearly presented until now. In addition, since the working force in the strut may increase depending on the depth of excavation or the soil condition of the backfill, the magnitude of the pre-loading that can be applied to the brace may decrease. Nevertheless, the magnitude of the pre-loading (more than 50% of the working load) proposed by the previous research results has been uniformly applied to the strut. In this study, 3D finite element analysis was performed to evaluate the application range of the pre-loading of H-beam strut according to the soil conditions of backfill. As a result of the analysis, it was found that there is a very high possibility that a problem may occur in the stability of the structure of strut due to the earth pressure and the pre-loading when the soil condition is weak and deep excavation proceeds. And it was found that the application range of the pre-loading was 5%~70% of the working load in strut.

• Maritime Security
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• v.1 no.1
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• pp.241-271
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• 2020

The military technology currently receiving the most attention is the hypersonic missile. hypersonic is faster than the speed of sound or Mach 5+. The vast majority of the ballistic missiles that it inspired achieved hypersonic speeds as they fell from the sky. Rather than speed, today's renewed attention to hypersonic weapons owes to developments that enable controlled flight. These new systems have two sub-varieties: hypersonic glide vehicles and hypersonic cruise missiles. Hypersonic weapons could challenge detection and defense due to their speed, maneuverability, and low altitude of flight. The fundamental question of this study is: 'What effect will the hypersonic missile have on the maritime strategy?' It is quite prudent to analyze and predict the impact of technology in the development stage on strategy in advance. However, strategy is essential because it affect future force construction. hypersonic missiles act as a limiting factor in securing sea control. The high speed and powerful destructive power of the hypersonic missile are not only difficult to intercept, but it also causes massive ship damage at a single shot. As a result, it is analyzed that the Securing sea control will be as difficult as the capacity of sea denial will be improved geographically and qualitatively. In addition, the concept of Fortress Fleet, which was criticized for its passive strategy in the past, could be reborn in a modern era. There are maritime power projection/defence, SLOC attack/defence in exploiting sea control. The effects of hypersonic missiles on exploiting sea control could be seen as both limiting and opportunity factors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.123-128
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• 2021

For accurate speed and current control in industrial applications, SRM (Switched Reluctance Motor) is very important to synchronize the stator phase excitation and rotor position in the drive due to its nature. In general, position sensors such as encoder and resolver are used to generate rotational force by exciting the stator winding according to the rotor position and to control the motor by using speed and position information. However, for these sensors, 1) the cost of the sensors is quite large in terms of price, so the proportion of the motor system to the total system cost is high. 2) In terms of mechanical, position sensors such as encoders and resolvers are attached to the stator to increase the size and weight. In conclusion, in order to drive the SRM, control based on the rotor position information should be basically performed, and it is important to design the SRM driving system according to the environment in consideration of the application field. Therefore, in this paper, we intend to study the driving and control characteristics of SRM through variable switching duty control by designing a low-cost analog driving device, deviating from the general control system using the conventional encoder and resolver.

• Journal of the Korean GEO-environmental Society
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• v.22 no.3
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• pp.45-51
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• 2021

The evaluation of the degree of compaction of the embankment area, which accounts for most of highway earthworks, is generally performed by a flat plate loading test. The plate loading test is a traditional test method and has high reliability in the field. However, as reaction force equipment must be carried out and it takes about 40 minutes per site during the test, there may be limitations in managing the entire expanse of earthworks. Meanwhile, in order to overcome this, the Ministry of Land, Infrastructure and Transport proposed a simple method of evaluating the level of compactness in the provisional guidelines for compaction management of the packaging infrastructure in 2010. However, it has not been utilized at the highway construction site until now, 10 years later. Therefore, this study attempted to verify the utility of the compaction evaluation method using LFWD (Light Falling Weight Deflectometer) of the impact loading method among the test methods suggested in the provisional guideline. To this end, the correlation was derived by conducting a plate loading test and an LFWD test for each site property and compaction degree. As a result of the test, there was no consistency of test data in the ground with a relative compaction of 80% or less. However, it was confirmed that the correlation has a tendency to increase beyond that. If the test method or test equipment is improved to ensure the consistency of the test values of the impact loading method in the future, it will play a big role in solving the blind spot for compaction management in the earthworks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.1-9
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• 2020

As pet dogs rapidly increase in number, abandoned and lost dogs are also increasing in number. In Korea, animal registration has been in force since 2014, but the registration rate is not high owing to safety and effectiveness issues. Biometrics is attracting attention as an alternative. In order to increase the recognition rate from biometrics, it is necessary to collect biometric images in the same form as much as possible-from the face. This paper proposes a method to determine whether a dog is facing front or not in a real-time video. The proposed method detects the dog's eyes and nose using deep learning, and extracts five types of directional face information through the relative size and position of the detected face. Then, a machine learning classifier determines whether the dog is facing front or not. We used 2,000 dog images for learning, verification, and testing. YOLOv3 and YOLOv4 were used to detect the eyes and nose, and Multi-layer Perceptron (MLP), Random Forest (RF), and the Support Vector Machine (SVM) were used as classifiers. When YOLOv4 and the RF classifier were used with all five types of the proposed face orientation information, the face recognition rate was best, at 95.25%, and we found that real-time processing is possible.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.531-552
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• 2020

In the previous study, both the wave characteristics at the tip of composite breakwater and on caisson were investigated by applying olaFlow numerical model of three-dimensional regular waves. In this paper, the same numerical model and layout/shape of composite breakwater as applied the previous study under the action of one directional irregular waves were used to analyze two and three-dimensional spatial change of wave force including the impulsive breaking wave pressure applied to trunk of breakwater, the effect of rear region, and the occurrence of diffracted waves at the tip of caisson located on the high crested rubble mound. In addition, the frequency spectrum, mean significant wave height, mean horizontal velocity, and mean turbulent kinetic energy through the numerical analysis were studied. In conclusion, the larger wave pressure occurs at the front wall of caisson around the still water level than the original design conditions when it generates the shock-crushing wave pressure in three-dimensional analysis condition. Which was not occurred by two-dimensional analysis. Furthermore, it was confirmed that the wave pressure distribution at the caisson changes along the length of breakwater when the same significant incident wave was applied to the caisson. Although there is difference in magnitude, but its variation shows the similar tendency with the case of previous study.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.6
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• pp.409-415
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• 2021

Medical waste management is becoming increasingly important, specifically in light of the current COVID-19 pandemic, as hospitals, clinics, quarantine centers, and medical research institutes are generating tons of medical waste every day. Previously, a traditional incineration process was utilized for managing medical waste, but the lack of landfill sites, and accompanying environmental concerns endanger public health. Consequently, an innovative sterilization shredding system was developed to resolve this problem. In this research, we focused on the design and numerical analysis of a shredding system for hazardous and infectious medical waste, to establish its operational performance. The shredding machine's components were modeled in a CAD application, and finite element analysis (FEA) was conducted using ABAQUS software. Static, fatigue, and dynamic loading conditions were used to analyze the structural stability of the cutting blade. The blade geometry proved to be effective based on the cutting force applied to shred medical waste. The dynamic stability of the structure was verified using modal analysis. Furthermore, an S-N curve was generated using a high cycle fatigue study, to predict the expected life of the cutting blade. Resultantly, an appropriate shredder system was devised to link with a sterilization unit, which could be beneficial in reducing the volume of medical waste and disposal time, thereof, thus eliminating environmental issues, and potential health hazards.