• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.219-228
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• 2006

In urban areas, tunnelling induced ground deformations, particularly ground settlements should be considered in order to minimize the damage of adjacent structures. Therefore, an appropriate monitoring system for the tunnel construction should be setup at the planning or design stage. A number of studies on ground settlements due to tunnelling in soft ground have been carried out so far. However, most studies have focused on clay soil rather than sand soil. In particular, a few studies on behaviour of subsurface deformations in granular material have been reported. In this study, two-dimensional laboratory model test with aluminium rods regarded as continuum granular material and close range photogrammetric technique, and numerical analysis were carried out in order to identify the behaviour of subsurface deformations due to shallow tunnelling. Direction and magnitude of displacement vectors from the model test was identical to the numerical analysis. In particular, the vector direction was appeared to be toward a point below the tunnel invert level. A narrow 'chimney or tulip like' pattern of vertical displacement was confirmed by both the model test and numerical analysis. This is consistent with the field data. In addition to the qualitative comparison, the quantitative comparison of subsurface settlements according to 2D volume loss showed good agreement between the model test and numerical analysis. Therefore, close range photogrammetric technique applied in the model test may be used to validate the result from the continuum numerical analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.946-951
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• 2004

ITIS is applied to the several tunnel construction sites in Korea. Tunnel construction properties which are acquired from these sites are transferred to information management server(SQL 2000 server)by client application program in real time. Access permission to DB server depends on the user's roles. Some functions which cannot be embodied in SQL Server are serviced through XML and GMS server is used for spatial data based on GIS part. This system is supposed to give engineers the advantages which are not only easy handling of the program and computerized documentation on every information during construction but also analyzing the acquired data in order to predict the structure of ground and rock mass to be excavated later and show the guideline of construction. Neung-Dong tunnel and Mu-Gua express way tunnel are now under construction and with this system they have 3D visualized map of the geology and tunnel geometry and accumulate database of construction information such as tunnel face mapping results, special notes and pictures of construction and 3D monitoring data, all matters on the stability of rock bolts and shotcrete, and so on. Ground settlement prediction program included in ITIS, based on the artificial neural network(ANN) and supported by GIS technology is applying to the subway tunnel. This prediction tool can make it possible to visualize the ground settlement according to the excavation procedures by contouring the calculated result on 3D GIS map and to assess the damage of buildings in the vicinity of construction site caused by ground settlement.

• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.88-95
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• 1998

Vibration analysis of rotating machinery can give an indication of possible faults thus allowing maintenance before further damage occurs. Current predictive maintenance system installed in Pyung-tak has the ability to diagnose the mechanical problems within the LNG Pump when the vibration exceeds preset overall alarm levels. In this study, LNG pump auto-diagnosis system based upon Windows NT and DSP Board is developed. This system analysis velocity signal acquired from dual accelerometer input monitor system to diagnose pump condition. Many plots which display machine condition are shown and features of vibration are stored in every time. If the fault is found, the system diagnoses automatically using expert system and trend monitoring. Operator checks pump condition intuitively using personal computer monitor.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.262-274
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• 2010

In Welfare Center for the disabled, under the Government's information acceleration plan, the computer system has been developed starting from work standardization in 2001 but it has been emphasized only on the technical and customer convenience side leaving out preparation for the side effects of them. Therefore this article will seek the necessity of personal information protection, legal basis in the Welfare Center for the disabled. Additionally after analyzing current status for the personal security of Welfare Center for the disabled, establishing an alternative plan for personal security policy's way could be addressed. Increasing education for awareness stress of personal information security, and preparing institutional protection apparatus from applying life cycle of personal information would be an alternative plan for personal information protection for Welfare Center for the disabled. Also frequent monitoring of accessing personal information from the computerized system should be achieved. It is impossible to recover damage caused by leak of personal information although post actions are progressed. From this essay, awareness of personal information protection should be newly revised for both the Social Welfare Organization and the Disabled welfare center, and also technical, institutional strategy's action should be arranged.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.389-398
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• 2012

In this study, structural strain responses of the jacket-type Uldolmok tidal current power plant structure under severe tidal environments were measured and analyzed using long-term measurement system during construction and also operation. It was observed that there were significant changes in strain responses at the steps of jacket lifting, block loading, pile ejection and insertion. Strains due to dead loads and tidal loads were analyzed before and after removal of a jacket leg, and it was also found that the strains due to dead load were much significantly changed after jacket leg removal. From the measurement data during operation, it was found that strain responses were fluctuated with M2 and M4 tidal periods and also relatively short period of about 10 min due to the peculiar tidal characteristics in the Uldolmok strait. Finally, the neural network-based non-parametric estimation models were investigated to build up the signal-based structural damage monitoring system.

• Journal of Arbitration Studies
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• v.10 no.1
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• pp.92-113
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• 2000

Products liability refers to the liability of any or all parties along the chain of manufacture of any product for damage caused by that product. This includes the manufacturer of component parts (at the top of the chain), an assembling manufacturer, the wholesaler, and the retail store owner (at the bottom of the chain). Products containing inherent defects that cause harm to a consumer of the product, or someone to whom the product was loaned, given, etc., are the subjects of products liability suits. The goal of products liability system should be to maximize consumer welfare by efficiently providing just compensation for injuries incurred and deterring future injuries without unreasonably impeding the supply of the goods and services to consumers. Some advanced countries, apart from relying on products liability systems, also apply other policies and legislation directly aimed at the safety of the consumer. The application of general safety policies as well as products liability rules is not costless. An efficient system will not eliminate risk from society. An efficient system ... that maximises consumer welfare ... maximises the benefits while minimising the costs. Products liability claims can be based on negligence, strict liability, or breach of warranty of fitness depending on the jurisdiction where the claim is based. In view of international business and law circumstances, it should be stressed that international enterprises in Korea should consider how to cope with the situation of international transaction. International enterprises should have a correct perception about products liability which is to contribute the stabilization and improvement of the people's life and the sound develpement of the national economy. Products liability system creates incentives that influence behaviour and performance in ways that are desirable, such as more diligent monitoring to prevent defective products from reaching the market-place. At the same time, any liability system will impose burdens that are undesirable, such as greater costs imposed on business and consumers and reduced avaiability of consumer goods. The concern for society is to balance. The ideal situation is where the cost imposed on producers of goods and services pushes them to a desirable level of care but not so far that producers reach undesirable level of caution that may deprive consumers unnecessarily of the benefits from new and innovative products.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.3
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• pp.233-239
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• 2004

Smart material is used in various applications such as for glass frame, for medical instruments and for a part of sensors. Smart composite materials ran be applied to a part of aircraft and to the on-line monitoring system for industrial structures, using the shape memory effect. However, it is very difficult to simulate and analyze the shape memory effect in smart composites. In this paper, a two dimensional axisymmetric model was proposed to analyze the smart composite of one fiber and matrix using the finite element method(FEM). The finite element analysis was carried out in two renditions of the room temperature(293K) and a higher temperature (363K). The results we.e compared with the experimental results to confirm the validity of the analysis. In addition, the acoustic emission(AE) technique was used to study the microscopic damage behavior and the effect of pre-strains on TiNi/A16061 shape memory alloy composite.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.336-346
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• 2009

As a follow-up survey of A Study of Monitoring Method on Exposure Level and Biomarkers of Environmental Pollutants-Focused on Ulsan Industrial Comlpex Area, published in 2005, a close examination of the health status was conducted for selected Ulsan residents. Based on the previous study, a total number of 129 subjects were divided into two groups: the exposure group consisted of 39 residents whose blood levels of lead, mercury and/or cadmium were higher than international reference values, and 90 residents of control group with normal levels. Environmental exposure level and its association with health condition were examined by various methods such as questionnaire, analyses of lead, mercury and cadmium in blood and medical examinations. The geometric mean concentrations of lead, mercury and cadmium in blood were respectively $2.07{\mu}g/d{\ell}$ (exposure $2.54{\mu}g/d{\ell}$, control $1.90{\mu}g/d{\ell}$), $5.94{\mu}g/L$ (exposure $8.57{\mu}g/L$, control $5.07{\mu}g/L$), $1.32{\mu}g/L$ (exposure $1.30{\mu}g/L$, control $1.33{\mu}g/L$). The concentrations of the three heavy metals in blood showed lower levels than internationally recommended values except for blood mercury. Also, any abnormal or, peculiar disease, or target tissue damage related to the heavy metals was not observed among the all subjects. Therefore, it can be said that no significant difference of heavy metal concentrations and health conditions was found between the two groups.

• Journal of Environmental Health Sciences
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• v.14 no.2
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• pp.1-12
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• 1988

Airborne dust and asbestos fiber concentrations were determined in subway stations located in Seoul area. Two stations, such as Eulchiro 4-Ka Station of Line #2, constructed during a period of 1980-1984 and Hyehwa Station of Line #4, opened in 1985, were selected. The results of the study are as follows. 1. Daily time-weighted average (TWA) concentrations of airborne dusts from 07:00 to 20:00 hours in Line #2 and Line #4 were 0.43$\pm$0.08 mg/m$^3$ and 0.37$\pm$0.12 mg/m$^3$, respectively. Thus, the dust levels in Line #2 were significantly higher than the levels in Line #4 (p < 0.05). 2. Dust levels in the morning (07:00-11:00 hours), noon (11:00-16:00 hours) and in the evening (16:00-20:00 hours) in Line #2 were 0.47$\pm$0.17 mg/m$^3$, 0.37$\pm$0.08 mg/m$^3$, and 0.46$\pm$0.07 mg/m$^3$ respectively. Thus, dust levels in the morning and evening (i.e., during rush hours) were significantly higher than levels in the noon (p < 0.02). However, there was no such difference in dust levels by time in Line #4. 3. Airborne total dust concentrations were well below the occupational health standard of 10 mg/m$^3$, however, the levels were exceeding the ambient air standard recommended by the Korean Environment Administration. 4. All of airborne asbestos fiber concentrations were equal to or below 0.005 fibers/cc. The levels are within both occupational health standards and U.S. EPA criteria. 5. A consideration should be given to the improvements of cleaning methods (such as use of vacuum cleaning instead of brushing) and the existing ventilation (such as more air change and filtration of supply air) for a reduction of dust levels. 6. It is recommended that routine monitoring of airborne dusts and asbestos fibers be conducted because more dusts and asbestos fibers can be produced in the air due to the deterioration of facilities by age and water damage in future.

• Geotechnical Engineering
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• v.12 no.5
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• pp.103-116
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• 1996

Man-made vibrations from traffic and construction activities are important because they may cause damage to structures. The current literature provides that damages in the urban areas were not caused by direct transmission of vibration, but rather through subsequent settlement caused by soil densification. In this paper. prediction technique of ground borne vibration induced settlement was introduced on the basis of case studies. In situ application technique of the settlement prediction model developed in laboratary was described, and the predicted settlement was compared with the measured settlement from case studies. The settlement from case studies hlatched well with the settlement calculated from the model. The parametric studies of settlement in typical urban site conditions were performed to determine the sensitive parameters and to develop reliable vibration monitoring and interpretation schemes. These demonstrated the potential usefulness of the model for the evaluation and prediction of the vibration induced in-situ settlement of sands.