• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.133-138
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• 2007

The balance shaft housing in the recent engines tends to have the high cycle fatigue crack caused by increased engine power. In this paper, a CAE procedure is introduced to predict the durability of the balance shaft housing. The procedure is performed through two analysis steps. In the first step, the multibody dynamic simulation is used to obtain more accurate loading boundary conditions applied to the finite element model for the following step. Next, the finite element analysis is performed to predict the durability of the balance shaft housing through the calculation of the safety factor. Through this CAE procedure, the revised balance shaft housing was developed to improve the durability. And the durability of the housing was confirmed experimentally.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8228-8233
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• 2015

This study was examined for perception of introduction and adaptation stages focused on the tourist police in Seoul Metropolitan Police Agency. Seoul Metropolitan tourist police operates that is installed the first in Korea. Through in-depth interviews, we collected and analyzed data on the purpose of the tourist police, operating direction, the areas of activity, job characteristics, working environment. Awareness about activities of the tourist police members can have a significant impact on tourist police installations in the future. The survey was conducted for tourist police officers 16 people in the Seoul Metropolitan Police Agency, and analysis of the data was carried out through a qualitative research analysis program NVivo 10.0. Recognition was divided that Start step, Trial-and-error step, Skilled step, Completion step from the work experience of the tourist police and it analyzed the difference between each step. Each stage found difference in the individuals, working periods, also it was confirmed that difference of opinion about the settlement and completeness in the tourist police.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.342-356
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• 2009

This paper presents a vote decision-based deinterlacing scheme for false directional error correction(VDD) to convert interlaced signal into non-interlaced signal using only one fields. The VDD using the vote decision goes through four steps process. The first step extracts regions having doubt of false edge using MM-ELA method. In these regions, the edge direction is decided by the majority vote using upper adjacent pixels's information through the second step. But, we still have undecided directions, which will be decided by the majority vote and the directional average decision at the third step. This step preserves the edge directions and minimizes visual degradation. Finally, the last step interpolates undecided pixels using DOI method which can consider the fine edge direction. Although the VDD with hierarchical structure has a high complexity, it can extract delicate edge compared to other pixel-by-pixel or window-by-window deinterlacing algorithms. Simulation results show that it has significantly improved both the subjective and objective qualities of the reconstructed images.

• Journal of Korean Physical Therapy Science
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• v.12 no.4
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• pp.69-77
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• 2005

The purpose of this study is to estimate how much the motility of affected and unaffected lower limb respectively would have effects on their ambulation through comparing the difference between their affected and unaffected lower limb and studying the correlation between such difference and their ambulation. In addition, the study also intends to find out remedial measures suitable for improving their ambulation with relevant physical treatment. To do this, a quantitative electromyogram(QEMG) test was done to hamstring of affected and unaffected lower limb so as to yield IP values. Based on such IP values, RMS(root mean square) values as the total sum of IP values were found with QEMG analysis system (made by Medelec Co.) and then the ambulation depending on the difference in muscular strength were analyzed by ink-foot print method as well as the corresponding statistics were processed by T-test through SPSS. The differences in muscular strength of hamstring in unaffected limbs of hemiplegic patients only affect stride length. It was statistically significant. The effect of difference in muscular strength of the hamstring in affected limb of hemiplegic patients on their ambulation was very different between strong and weak group in terms of walking velocity, step per minute, stride and step length, showing statistically significant difference(p<.05). Although there was a difference in the step length of the affected limb, it was not statistically significant(p>.05). For the unaffected hamstring, there were significant differences of stride length between in unaffected limb and in affected limb. For the affected hamstring, there were also significant differences in walking velocity, step per minute, stride and step length. Besides, it was found that the difference of the muscular strength between strong and weak group was at the highest.

• Journal of the Ergonomics Society of Korea
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• v.35 no.2
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• pp.85-95
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• 2016

Objective:The purpose of this study is to suggest the methodology for establishment of safety culture in industry. Background: There have been studies indicating positive relation between safety culture and safety performance. But the areas of those efforts have been mainly focused on elements or factors consisting of safety culture. So it is expected that studies on methodologies for developing process of the culture could contribute for the industry to understand and apply it accordingly in order to improve their practices. Method: In this study, the scope was considered just for industry, even though there are many fields of culture. As the first step, the limitations of regulatory control and efforts by industry were reviewed, and the trends of researches were presented. In the second step, the global company practices were provided with detailed activities. Results: This paper showed the limitations of present state in government strategies and industry for safety culture improvement. Also the restricted areas in researches were shown. As one of the solutions to resolve those things, such global company practices as perception to safety journey, the steps of culture development, total safety philosophy, structure and elements of safety process, standards and procedures, training, and up to keys to success were suggested. Conclusion: Through this study, the development of the structure of safety process which consists of many purposeful activities has been derived to be very important. Because it will be the seeds of safety culture expressing their thinking process and behaviors. Also it is required to approach success step by step according to the achievement of each step. Application: This study can be used to develop the methodology and safety process in industry with different viewpoints for safety culture establishment.

• Journal of Korea Water Resources Association
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• v.50 no.8
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• pp.579-586
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• 2017

In order to analyze the quantitative water withdrawal amount of intake pipe with functional screen and to evaluate the improvement effect of the suspended solid and turbidity through the filter media, four-step research methods were suggested. In the first step, laboratory scale experiments were constructed to determine the constitution method of the sample device filter media. In the second step, sample device was constructed and the flow rate was observed through intake pipe with functional screen. In the third step, flow rate was observed at different turbidity conditions for each filter material, and the hydraulic conductivity was estimated using MODFLOW. Finally, numerical model was constructed with the MODFLOW for the sample device and the estimated hydraulic conductivities were applied to the third step and the amount of water withdrawal was analyzed. As a result of applying hydraulic conductivity at 0 NTU, 39.96% more withdrawal was calculated than the observed flow rate. On the other hand, when hydraulic conductivity was applied at 100~120 NTU, the difference in flow rates was 9.41%.

• Smart Structures and Systems
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• v.26 no.6
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• pp.681-692
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• 2020

Conventional Piezoelectric Energy Harvesters (CPEH) have been extensively studied for maximizing their electrical output through material selection, geometric and structural optimization, and adoption of efficient interface circuits. In this paper, the performance of Stepped Piezoelectric Energy Harvester (SPEH) under harmonic base excitation is studied analytically, numerically and experimentally. The motivation is to compare the energy harvesting performance of CPEH and SPEHs with the same characteristics (resonant frequency). The results of this study challenge the notion of achieving higher voltage and power output through incorporation of geometric discontinuities such as step sections in the harvester beams. A CPEH consists of substrate material with a patch of piezoelectric material bonded over it and a tip mass at the free end to tune the resonant frequency. A SPEH is designed by introducing a step section near the root of substrate beam to induce higher dynamic strain for maximizing the electrical output. The incorporation of step section reduces the stiffness and consequently, a lower tip mass is used with SPEH to match the resonant frequency to that of CPEH. Moreover, the electromechanical coupling coefficient, forcing function and damping are significantly influenced because of the inclusion of step section, which consequently affects harvester's output. Three different configurations of SPEHs characterized by the same resonant frequency as that of CPEH are designed and analyzed using linear electromechanical model and their performances are compared. The variation of strain on the harvester beams is obtained using finite element analysis. The prototypes of CPEH and SPEHs are fabricated and experimentally tested. It is shown that the power output from SPEHs is lower than the CPEH. When the prototypes with resonant frequencies in the range of 56-56.5 Hz are tested at 1 m/s2, three SPEHs generate power output of 482 μW, 424 μW and 228 μW when compared with 674 μW from CPEH. It is concluded that the advantage of increasing dynamic strain using step section is negated by increase in damping and decrease in forcing function. However, SPEHs show slightly better performance in terms of specific power and thus making them suitable for practical scenarios where the ratio of power to system mass is critical.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.75-83
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• 2023

As part of a study to analyze the excessive camber occurring in prestressed concrete railway bridges, this paper presents a calculation method and analysis results for the creep coefficient which defines the increase in camber of a concrete structure over time. Using the creep coefficient formula of the design code, the coefficient is obtained by applying the climatic conditions (relative humidity and temperature) of 12 regions in Korea. The effects of differences in climatic conditions by region and starting time of load on the creep coefficient are analyzed. In order to properly calculate the creep, most of which occurs in the early stages of loading, a detailed analysis is performed by applying a time step analysis method to consider varying climate conditions through loaded period. The creep coefficient obtained by applying the average climate conditions of the region is similar to the average of the creep coefficients obtained by time step analysis. Through time step analysis, it is shown that the offset and overlap effects of relative humidity and temperature on the creep coefficient and the climate effect at the time of initial loading can be appropriately represented.

• Journal of the Korean Geographical Society
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• v.47 no.3
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• pp.426-439
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• 2012

The goal of this study is to propose a new method to capture the qualitative person spatial behavior. Beyond tracking or indexing the change of the location of a person, the changes in the relationships between a person and its environment are considered as the main source for the formal model of this study. Specifically, this paper focuses on the movement behavior of a person near the boundary of a region. To capture the behavior of person near the boundary of regions, a new formal approach for integrating an object's scope of influence is described. Such an object, a spatio-temporally extended point (STEP), is considered here by addressing its scope of influence as potential events or interactions area in conjunction with its location. The formalism presented is based on a topological data model and introduces a 12-intersection model to represent the topological relations between a region and the STEP in 2-dimensional space. From the perspective of STEP concept, a prototype analysis results are provided by using GPS tracking data in real world.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.177-183
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• 2015

The purpose of ICT Healing platform is the prevention of chronic disease. It is intended to early warning of the disease through the information such as the bio-signals and lifestyle. In this paper, we provide a 2-Step open system(TOS) for personalized health data access. TOS is connected between the personal health related data providers and service providers of individuals ICT Healing platform, a software engine for relaying personalized health data. The proposed system, to operate in isolation to 2 step in personal health document repository Inbound module and Outbound module to provide an inquiry service to external organizations. Therefore, we propose a personalized editable Manifest concept for defining data exchange between Step. This can be used as a reference model to collect the personal health information is scattered in many health related service institutions (Hospitals, Fitness Centers, Health Examination Centers, Personal Health Device, etc.) and under private-led liberalization.