• Convergence Security Journal
• /
• v.21 no.1
• /
• pp.107-113
• /
• 2021

Recently, large-scale research and efforts aimed at the smart world such as smart city, smart home, smart transportation, and smart care are continuing. As these smart worlds become more common, the expansion of connectivity with the Internet and the threat of cyber terrorism will be inevitable. Increasing the threat of cyber terrorism is increasing the likelihood of a massive disaster and safety accident. Therefore, in this paper, we examine smart worlds that are expanded in various forms and derive the security threat factors that smart worlds have. In addition, it is proposed to block the threat of terrorism from abroad if access from abroad is not required when constructing a smart world. Through this, we intend to present a method to eliminate cyber terror threats for the establishment and operation of a safe smart world.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.3
• /
• pp.104-111
• /
• 2019

A separate type rotary engine consisting of a compressor and an expander is under development. The engine motoring, compressor pressure, and fuel combustion have been tested with the initial prototype for operability checks of the mechanism. This paper describes an engine cycle analysis method designed specifically for this new-concept engine. The unique operational mechanism of the engine and the thermodynamic properties of each step of air intake, compression, filling of combustion chamber, combustion, expansion and exhaust were analyzed. The cycle efficiencies of this engine according to various engine design parameters as well as the cooling effect of compressed air between the compressor and expander can be easily calculated with this method; further, some case studies are presented in this paper.

• Knowledge Management Research
• /
• v.20 no.2
• /
• pp.105-135
• /
• 2019

This study investigates cognitive and emotional changes in individuals to clarify the principle between artistic stimulation and business innovation idea generation based on phenomenological research methodology. We conducted in-depth interviews with six participants who participated in the artistic creation program of business art, and derived meanings from their experience. As a result, we presented 4 essential categories, 8 main subjects, and 20 sub-subjects; 1) Optimizing rational and creative thinking, 2) Projecting oneself to the artist, finding balance, 3) Having room in mind to view the surroundings, finding insight into the world, 4) Eureka moment, crossing the boundary between business and art. We also found out participants of the program 1) Gradually expanded the criteria, 2) In chaotic directions, and 3) Leaded business creativity through from a non-form to reality throughout the project experience, The attempt to identify business phenomena by using phenomenological qualitative research methods had an academic significance regarding the unfamiliarity of the method in the business administration area. Moreover, this study broadened the possibility of promoting creativity by art in business areas. The study verified the categories and subjects of the business art, paving the way towards application in the real business situation.

• Journal of the Korean Institute of Gas
• /
• v.22 no.6
• /
• pp.40-43
• /
• 2018

For pressure safety valves, open failure and close failure are partially dependent on each other. A method is proposed in this work that uses a Markov process model and a Weibull distribution model in order to construct a reliability model for two kinds of failure. A pressure safety valve model is obtained from a known open failure model, an induced close failure model, and a simultaneous failure model that reproduces recently reported inspection results. It is expected that the application of the proposed method can be expanded to quantitative risk assessment of various systems that have partially dependent multiple failure states.

• Journal of the Korean Society of Safety
• /
• v.33 no.6
• /
• pp.37-41
• /
• 2018

Process safety technology has developed from qualitative methods such as HAZOP (hazard and operability study) to semi-quantitative methods such as LOPA (layer of protection analysis), and quantitative methods are actively studied these days. Quantitative risk assessment (QRA) is often based on fault tree analysis (FTA). FTA is efficient, but difficult to apply when failure events are not independent of each other. This problem can be avoided using a Markov process (MP). MP requires definition of all possible states, and thus, generally, is more complicated than FTA. A method is proposed in this work that uses an MP model and a Weibull distribution model in order to construct a reliability model for multiple dependent failures. As a case study, a pressure safety valve (PSV) is considered, for which there are three kinds of failure, i.e. open failure, close failure, and gas tight failure. According to recently reported inspection results, open failure and close failure are dependent on each other. A reliability model for a PSV group is proposed in this work that is to reproduce these results. It is expected that the application of the proposed method can be expanded to QRA of various systems that have partially dependent multiple failure states.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.3
• /
• pp.1434-1449
• /
• 2019

Video object segmentation is a significant task in computer vision, but its performance is not very satisfactory. A method of video object segmentation using weakly temporal information is presented in this paper. Motivated by the phenomenon in reality that the motion of the object is a continuous and smooth process and the appearance of the object does not change much between adjacent frames in the video sequences, we use a feed-forward architecture with motion estimation to predict the mask of the current frame. We extend an additional mask channel for the previous frame segmentation result. The mask of the previous frame is treated as the input of the expanded channel after processing, and then we extract the temporal feature of the object and fuse it with other feature maps to generate the final mask. In addition, we introduce multi-mask guidance to improve the stability of the model. Moreover, we enhance segmentation performance by further training with the masks already obtained. Experiments show that our method achieves competitive results on DAVIS-2016 on single object segmentation compared to some state-of-the-art algorithms.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.6
• /
• pp.348-357
• /
• 2021

In this paper, the generalized hydrodynamic force and response of a flexible body are calculated at different reference coordinate systems. We generalize the equation of motion for a flexible body by using the conservation of momentum (Mei et al., 2005). To obtain the equations in the generalized mode, two different reference coordinates are adopted. The first is the body-fixed coordinate system by a rigid body motion. The other is the inertial coordinate system which has been adopted for the analysis. Using the perturbation scheme in the weakly-nonlinear assumption, the equations of motion are expanded up to second-order quantities and several second-order forces are obtained. Numerical tests are conducted for the flexible barge model in head waves and the vertical bending is only considered in the hydroelastic responses. The results show that the linear response does not have the difference between the two formulations. On the other hand, second-order quantities have different values for which the rigid body motion is relatively large. However, the total summation of second-order quantities has not shown a large difference at each reference coordinate system.

• Nuclear Engineering and Technology
• /
• v.54 no.4
• /
• pp.1374-1381
• /
• 2022

Under the influence of nuclear radiation, the reliability of steam generators (SGs) is an important factor in the efficiency and safety of nuclear power plant (NPP) reactors. Motion planning that remotely manipulates an SG mobile tube-inspection robot to inspect SG heat transfer tubes is the mainstream trend of NPP robot development. To achieve motion planning, conditional traversal is usually used for base position optimization, and then the A^* algorithm is used for path planning. However, the proposed approach requires considerable processing time and has a single expansion during path planning and plan paths with many turns, which decreases the working speed of the robot. Therefore, to reduce the calculation time and improve the efficiency of motion planning, modifications such as the matrix method, improved parent node, turning cost, and improved expanded node were proposed in this study. We also present a comprehensive evaluation index to evaluate the performance of the improved algorithm. We validated the efficiency of the proposed method by planning on a tube sheet with square-type tube arrays and experimenting with Model SG.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.28 no.1
• /
• pp.53-61
• /
• 2022

Purpose: As the medical environment changes, the size of medical facilities continues to change. Of course, it is not easy to analyze the correlation between changes in the medical environment and changes in facility size in a rigorous scientific method. However, the results of investigating and analyzing changes in the size that occurred for any cause be able to serve as important references for future medical facility architectural plans. Methods: This study surveyed 68 general hospitals in Seoul for 15 years from 2005 to 2020. The change in the number of beds was investigated with data from the Ministry and Welfare. The gross area change was confirmed by analyzing the of all hospitals. Results & Implications: As a result of the survey, general hospitals in Seoul show a common phenomenon in which all hospitals except one case have expanded their size in the direction of increasing the gross area per bed over the past 15 years. However, in the method, a relatively small hospital with less than 500 beds mainly chose to reduce the number of beds. Large hospitals increased both the number of beds and the gross area, however showed a significant increase in the gross area.

• Journal of Korean Public Health Nursing
• /
• v.23 no.1
• /
• pp.113-128
• /
• 2009

Purpose: To explore the barriers and solutions of immunization programs for children among vulnerable classes in the position of service providers in Community health centers. Method: Data were collected through focus group interviews with 3 groups (17 providers), and were analyzed according to the analytic method of Morgan (1998) and Krueger (1998). Results: The following five categories were identified: difficulties in obtaining a list of children among vulnerable classes, difficulties in first contact with them, difficulties in up-to-date immunization, various difficulties according to the types of vulnerable family and suggestions of solution. These results indicated that there are many difficulties in providing expanded immunization service for children among vulnerable classes in terms of manpower, cooperation of departments in public health centers and linkages between health and welfare. Finally, the characteristics of the types of vulnerable family need to be elucidated. Conclusion: To increase immunization rates among children of vulnerable classes, policies need to be prepared at the public health organization itself and the linkages between health and welfare and need for hiring additional personnel.