• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.261-266
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• 2012

In this study, soil environmental impact assessment using risk-based approach was compared with that using concentration-based approach. For this, heavy metal contaminant exposure was characterized in an abandoned mine area. According to the estimated carcinogenic and non-carcinogenic risks, soil ingestion was identified as the most dominant exposure pathway. When contaminant concentrations exceeded the Korean Soil Contamination Warning Standards, their corresponding risk values also exceeded the Total Soil Risk Standard. Even the cases of satisfying the Korean Soil Contamination Warning Standards mostly showed higher risk levels than the Total Soil Risk Standard, re-confirming a more sensitivity of the risk-based assessment than concentration-based assessment. However, the in-depth analysis of the estimated non-carcinogenic risk values revealed a few cases for soil contact pathway showing contaminant concentrations higher than the Korean Soil Contamination Warning Standards although their non-carcinogenic risk values satisfied the level of Hazard Index Standard. The findings from this study support a necessity of shifting policy paradigm from concentration-based approach into risk-based approach for reliable risk assessment in abandoned mine areas, and also suggest a necessity of further fundamental studies regarding risk factors and standards.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.3
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• pp.347-353
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• 2012

Recently, multi-functionalization (as in smart phones) has been in demand, and the connectors connecting the electrical signals of each board in a cellular phone have become key components. The miniaturization of these connectors is required to achieve a finer pitch design and enhance the electrical signal transfer capacity. However, the miniaturization of connectors reduces the structural safety, and a finer pitch design may cause contact problems under external impact. In this paper, a preliminary design for miniaturized, finer-pitch connectors is suggested for a product with 50 pins and a thickness of 0.2 mm. The assembly process of the FPCB (Flexible Printed Circuit Board) and connector was simulated to ensure the holding force between the two components and avoid overstressing. The design optimization process was performed with the Taguchi method. Fatigue analysis was also conducted to predict the fatigue life of the terminal, and the theoretical and experimental results were compared.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.123-131
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• 2015

Modern is the era of convergence. In the complex position of the company to survive in the rapid environmental changes it can not be a mandatory fusion rather than choice. Wind convergence also in the art can be said to castration. This phenomenon can be found in many real life. Most real-life contact with the service sector is no exception. Due to a number of banks and insurance combined Banca named fusion of French banking and insurance business are integrated. Even recently, the situation has been provided by Investment consulting, equity trading services within bank branches. In this study, based on the need for convergence of corporate businesses convergence factors examined through regression analysis on whether any impact on the financial aptitude. External environmental factors that make up the fusion research factors internal environmental factors, both core competencies were factors to affect financial performance.

• The Korean Journal of Community Living Science
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• v.27 no.4
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• pp.739-753
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• 2016

This study was performed to identify the tendency and benefits of outdoor recreation in rural areas. The preferences and importance of the benefits of outdoor recreation activities in rural areas were simultaneously compared and analyzed through the discussion of a four quadrants portfolio map using importance-performance analysis. The social benefits in quadrant i had the characteristics of 'sharing nice experiences with others', 'having contact/interchange with others', 'colleagueship/helping each other', 'being together with friends', and 'making new friends.' These social benefit types were perceived as very important characteristics, but the real level of achievement was rather low. Thus it seems necessary, in the process of program development, to apply the social benefit types to the characteristics of the participants. The experience of nature and relaxation benefits in quadrant ii had the characteristics of 'relaxation and recreation', 'understanding nature', 'nature experience', 'getting away from everyday life', and 'experiencing new things.' These benefits and experience of nature were regarded as very important characteristics by the participants in outdoor recreation and, at the same time, their real achievements were highly recognized, thus they seemed to be proper types for the goals involved in developing an outdoor recreation activity program in rural areas. The personal and challenge benefits in quadrant iv had the characteristics of 'training of mental ability', 'improvement of self-esteem', 'fitness', 'increase in determination', 'possible danger', 'achievement', 'excitement', and 'adventure.' These benefits had less importance to the participants, but had relatively high achievement, thus it might be important to make further suggestions for the direction of development according to the participants' tendency, seasons and facilities.

• Journal of Biomedical Engineering Research
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• v.28 no.6
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• pp.811-816
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• 2007

The social activities of the elderly have been increasing as our society progresses toward an aging society. As their activities are increased, the occurrence of falls that could lead to fractures are increased. Falls are serious health hazards to the elderly and we need more thorough understanding of falls including the progress of falls and the impact area in various fall directions. Many of the traditional methods of falls research dealt with voluntary falls by younger subject since older subject can easily get fracture from voluntary falls. So, it has been difficult to get exact data about falls of the elderly. Here, we tried to capture the characteristics of the movements of major joints using three dimensional motion capture system during falls experiments using a moving mattress that can safely induce unexpected falls. Healthy younger subjects participated in the actual falls experiment and the moving mattress was actuated by a pneumatic system. The kinematic parameters such as velocities and accelerations of major segments were imported to a computer simulation environment and falls to hard surfaces were simulated in a computational environment using a realistic human model of aged persons. The simulation was able to give approximations to contact forces which can occur during actual falls.

• Journal of Environmental Health Sciences
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• v.41 no.2
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• pp.133-145
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• 2015

Objectives: Food safety has become one of the major public-concerning issues in Korea. In order to set guidelines to create manuals for the response to a food safety crisis by food industry, this paper classified food safety crises and suggested techniques to determine crisis level. Methods: This study clarified common terminologies and definitions including in food safety crises. It reviewed various food safety crises and described characteristics, types, and states of crises. Results: The results of this study suggested that a food safety crisis implied a situation in which hazards/risk spreading in the food supply chain was widely described, causing strong public concern followed by a socioeconomic impact, and therefore, requiring the implementation of a prompt and full response regarding the situation. In terms of seeking response plans, food safety crises might be classified according to the penalties resulting from violations of laws and regulations, causative substances, stages of the food supply chain, and first contact point for incidents. The crisis level for a food safety crisis could be classified according to its severity parameters. The guideline matrix was divided into four major stages: Blue/guarded, Yellow/elevated, Orange/high, and Red/severe. This study also suggested several methods for determining the crisis level, such as the simple judgement method, scoring methods using a check-list and a weighted check-list. Conclusion: The severity of related parameters might be of great importance in understanding a crisis and determining response options/challenges for crisis levels.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.1007-1015
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• 2000

This paper proposes an adaptive trajectory generation strategy of using on-line ZMP information and an impedance control method for biped robots. Since robots experience various disturbances during their locomotion, their walking mechanism should have the robustness against those disturbances, which requires an on-line adaptation capability. In this context, an on-line trajectory planner is proposed to compensate the required moment for recovering stability. The ZMP equation and sensed ZMP information are used in this trajectory generation strategy. In order to control a biped robot to be able to walk stably, its controller should guarantee stable footing at the moment of feet contacts with the ground as well as maintaining good trajectory tracking performance. Otherwise, the stability of robot will be significantly compromised. To reduce the magnitude of an impact and guarantee a stable footing when a foot contacts with the ground, this paper. proposes to increase the damping of the leg drastically and to modify the reference trajectory of the leg. In the proposed control scheme, the constrained leg is controlled by impedance control using the impedance model with respect to the base link. Computer simulations performed with a 3-dof environment model that consists of combination of a nonlinear and linear compliant contact model show that the proposed controller performs well and that it has robustness against unknown uneven surface. Moreover, the biped robot with the proposed trajectory generator can walk even when it is pushed with a certain amount of external force.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1423-1430
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• 2003

In this paper, we develop a real time monitoring system to detect third-party damage on natural gas pipeline. When the damage due to third-party incidents causes an immediate rupture, the developed on-line monitoring system can help reducing the sequences of event at once. Moreover, since many third-party incidents cause damage that does not lead to immediate rupture but can grow with time, the developed on-line monitoring system can execute a significant role in reducing many third-party damage incidents. Also, when the damage is given at a point on natural gas pipeline, the acoustic wave is propagated very fast about 421.3 m/s. Therefore, the data processing time should be very short in order to detect precisely the impact position. Generally, the pipeline is laid under ground or sea and the length is very long. So a wireless data communication method is recommendable and the sensing positions are limited by laid circumstance and setting cost of sensors. The calculation and monitoring software is developed by an algorithm using the propagation speed of acoustic wave and data base system based on wireless communication and DSP systems. The developed monitoring system is examined by field testing at Balan pilot plant, KOGAS being done in order to demonstrate its validity through reactive detection of third-party contact with pipelines. Furthermore, the development system was set at the practical pipelines such as an offshore pipeline between two islands Yul-Do and Youngjong-Do, and a land branch of Pyoungtaek, Korea and it has been operating in real time.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.182-193
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• 2011

The aim of this paper is to present the methodology for hand tracking and hand gesture recognition. The detected hand and gesture can be used to implement the non-contact mouse. We had developed a MP3 player using this technology controlling the computer instead of mouse. In this algorithm, we first do a pre-processing to every frame which including lighting compensation and background filtration to reducing the adverse impact on correctness of hand tracking and hand gesture recognition. Secondly, YCbCr skin-color likelihood algorithm is used to detecting the hand area. Then, we used Continuously Adaptive Mean Shift (CAMSHIFT) algorithm to tracking hand. As the formula-based region of interest is square, the hand is closer to rectangular. We have improved the formula of the search window to get a much suitable search window for hand. And then, Support Vector Machines (SVM) algorithm is used for hand gesture recognition. For training the system, we collected 1500 hand gesture pictures of 5 hand gestures. Finally we have performed extensive experiment on a Windows XP system to evaluate the efficiency of the proposed scheme. The hand tracking correct rate is 96% and the hand gestures average correct rate is 95%.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.405-416
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• 2005

The rubblization technique is breaking the aged concrete pavement slab into rubblized concrete aggregate, and use it as an base material at its original position, then builds overlay above the rubblized base. This method has been successively used in USA due to the advantage of good contructibility, cost-effectiveness as well as the capability of preventing of reflection cracks. However, constructibility and economic performance of rubblization on typical Korean concrete pavements needed to be investigate since to typical Korean concrete pavements have thick slab, as well include lean concrete subbase course. This stud explored optimum breaking depth and suggested minimum 10cm based on reflection crack simulation test. Also proper head shape and impact energy were investigated based on small breaking field tests. It was found that $127kg/cm^2$ of stress with 52.3% of head contact area are breaking requirement. Also, Multi-head type breaker suitable for Korean condition was designed and developed. This multi-head type breaker was designed to rubblize old concrete to the suggested optimum rubblized-depth and rubblized-concrete-aggregate size to prevent reflection crack and maintain high bearing capacity. This machine was used for the test of rubblization of old concrete pavement on a non-use old concrete and a in-serviced road. In these two tests, engineering properties of rubblized base and constructability and cost were investigated. In both tests, the old concrete rubblized to targeted size and depth, and high-level bearing capacity was achieved. Also, superior constructability and lower cost compared with traditional reconstruction was examined.