• Journal of the Korean GEO-environmental Society
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• v.13 no.6
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• pp.91-100
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• 2012

Wireless monitoring system for the structural health evaluation has a limit to the reliability of measured response. The objective of this study is to evaluate an effective measurement range of the wireless monitoring system on the analyzed data. For the wireless monitoring system, Bluetooth and Wi-Fi are applied to datalogger-receiver and receiver-personal computer, respectively. For the model of the monopile structure response, a laboratory-scale monopile is manufactured with Mono Cast Nylon and a lateral loading is applied by hammer impacting. Strain gauges attached on the model monopile are connected with the datalogger. The distances of datalogger-receiver and receiver-personal computer are changed for the evaluation of the measurement range. Experimental results show that the receiving rates of the response remain almost constant within limited distance, while the receiving rates dramatically decrease out of effective range. In addition, the receiving rates affect on the measured natural frequencies of the model monopile. This study suggests that the effective range evaluation of the wireless monitoring system may be used for the determination of a monitoring distance to the monopile installed in the offshore wind farm.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.43-50
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• 2011

The scope of the problems that could be solved by monitoring and the improvement of the recognition time is directly correlated to the performance of the management function of the business process. However, the current event-managing monitoring system and the real-time advanced alarming business monitoring system decided whether to apply warnings or not by assuming a fixed environment and showing expressions based on the design rules. Therefore, there is a limit for distinguishing the range of occurrence and the level of severity in regard to the new external problems occurring in a complicated environment. Such problems cannot be abstracted. In this paper, evaluation model of business process contextual situations using goal scenario is suggested to provide constant services through the current monitoring process in regard to the service demands of the new scenario which occurs outside. The new demands based on the outside situation are analyzed according to the target scenario for the process activities. Also, a similar process model is found and identified by combining similarity and interrelationship. The process can be stopped in advance or adjusted to the wanted direction.

• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.439-454
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• 2013

UN-REDD (United Nations programme on Reducing Emissions from Deforestation and forest Degradation) is currently being emerged as one of important mechanism to reduce carbon dioxide in relation to the deforestation. Although administrative boundary has already gained world-wide recognition as a typical method of monitoring unit in the process of GHG (Greenhouse Gas) reduction project, this approach did not provide a realistic evidence in the carbon sequestering monitoring in terms of UN-REDD; the meaningful comparison of land use patterns among watershed boundaries, interpretation for distribution trends of carbon density, calculation of opportunity cost, leakage management, etc. This research proposes a comparative evaluation framework in a more objective and quantitative way for carbon sequestering monitoring between administrative and watershed boundary approaches. Mt. Geumgang of North Korea was selected as a survey objective and an exhaustive and realistic comparison of carbon sequestration between the two approaches was conducted, based on change detection using TM satellite images. It was possible for drainage boundary approach to identify more detailed area-wide patterns of carbon distribution than traditional administrative one, such as estimations of state and trends, including historical trends, of land use / land cover and carbon density in the Mt. Geumgang. The distinctive changing trends in terms of carbon sequestration were specifically identified over the watershed boundary from 4.0% to 34.8% while less than 1% difference was observed in the administrative boundaries, which were resulting in almost 21-22%. It is anticipated that this research output could be used as a valuable reference to support more scientific and objective decision-making in introducing watershed boundary as carbon sequestering monitoring unit.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.263-274
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• 2019

The purpose of this study is to examine a monitoring method, management zones, and maintenance strategies for water friendly facilities in urban streams after the completion of ecological restoration projects. Maintenance monitoring items are composed of 'use space& facilities', 'trails& bike roads', 'access', and 'boards'. The evaluation standards of water friendly facilities are 'maintenance conditions', 'safety', and 'usage level' which are rated as 'good', 'moderate', and 'poor'. Through a field survey and evaluation of 15 stream sections in Jeonjucheon,the management levels of each water friendly facility are determined as 'priority maintenance', 'general maintenance', 'maintain/remove', and 'remove'. Based on the evaluation results, management zones and maintenance strategies are proposed for each stream section. As a results, the stream sections of J2, J3, J4, and J9 which have 5 to 9 facilities with 'priority maintenance' are determined as 'intensive management zone'. The stream sections of J5, J6, J7, J8, J11, and J14 which have 1 to 3 facilities with 'priority maintenance' are determined as 'regular management zone'. The stream sections of J1, J10, J12, J13, and J15 which have no facilities with 'priority maintenance' are determined as 'minimum management zone'. The process of monitoring & evaluation system and determining management zones can be applied to establish a systematic maintenance plan for water friendly facilities by participation of governance in the future.

• Journal of the Korean Society of Safety
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• v.36 no.1
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• pp.26-35
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• 2021

Governmental bodies generally conduct investigations for product safety management once new products are released to the market, in order to prevent distribution of illegal and defective items. Further, market surveillance activities are regularly conducted by the government to ensure distribution of safe products and recall any hazardous products. The safety investigations often involve a consumer monitoring system wherein consumer organizations participate in market monitoring to conduct surveys on illegal and defective products. As a result, the monitoring results of individual consumer organizations are available separately, but an integrated analysis of the data from all consumer organizations cannot be performed, thereby deterring comprehensive evaluation of the consumer monitoring system. In this study, we analyze the individual monitoring results of consumer organizations to understand the overall status and performance of comprehensive market monitoring and present the directions for desirable market surveillance policies. To this end, the effectiveness of market surveillance related to the distribution of products is verified through analysis of the interrelationships between the monitoring processes and performances of consumer organizations as well as their impact on the performances of the monitoring implementation processes; moreover, several improvement points and direction points are presented for more desirable monitoring of the consumer markets.

• Smart Structures and Systems
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• v.6 no.2
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• pp.135-146
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• 2010

This paper presents the perspective of the Structural Mechanics program of the Air Force Office of Scientific Research (AFOSR) on the damage assessment of structures for the period 2006-2009 when the author was serving as Program Manager at AFOSR. It is found that damage assessment of structures plays a very important role in assuring the safety and operational readiness of US Air Force fleet. The current fleet has many aging aircraft, which poses a considerable challenge for the operators and maintainers. The nondestructive evaluation technology is rather mature and able to detect damage with considerable reliability during the periodic maintenance inspections. The emerging structural health monitoring methodology has great potential, because it will use on-board damage detection sensors and systems, will be able to offer on-demand structural health bulletins. Considerable fundamental and applied research is still needed to enable the development, implementation, and dissemination of structural health monitoring technology.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.5
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• pp.39-45
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• 2006

Structural health monitoring has been conducted by non-destructive evaluation method when a turbine rotor system of an aircraft engine has cracks. Local stiffness of a turbine rotor system is degraded and critical speed is changed due to the presence of cracks in rotor. Critical speed which is affected by location and depth of crack, is obtained using compliance matrix of cracked rotor. The database of the obtained critical speed is used to evaluate structural health monitoring of a rotor system of a gas turbine engine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.84-87
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• 2001

The high speed machining which cam improve the production and quality has been remarkable in die/mold industry with the growth of parts and materials industries. The speed of machine tool increases, but on the other hand, the response of sensors I not being improved. Therefore, the condition monitoring techniques for the machine too, tool and workpiece in high speed machining are incomplete. In this study, characteristics of the tool edge roughness were verified from the high frequency components of cutting force signals acquired by the high speed dynamometer. Also, the experimental evaluation technique for the machinability and condition monitoring in high speed machining was established by analyzing the cutting force, acceleration and surface roughness.

• Journal of Ocean Engineering and Technology
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• v.19 no.4 s.65
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• pp.21-27
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• 2005

Large welded structures, including ships and offshore structures, are normally in operation under cyclic fatigue loadings. These structures include many geometric discontinuities, as well as material discontinuities due to weld joints. The fatigue strength at these hot spots is very important for the structural performance. In the past, various Non Destructive Evaluation (NDE) techniques have been developed to detect fatigue cracks and to estimate their location and size. However, an important limitation of most of the existing NDE methods is that they are off line; the normal operation of the structure has to be interrupted, and the device often has to be disassembled. This study explores the development of a structural health monitoring system, with a special interest in applying the technique to welded structural members in ship and offshore structures. In particular, the impedance based structural health monitoring technique that employs the coupling effect of piezoceramic (PZT) materials and structures is investigated.

• 한국터널공학회:학술대회논문집
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• 2005.04a
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• pp.189-201
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• 2005

Brittle failure has been detected in over-stressed rock mass during the construction of oil storage cavern. The main characteristics of stress induced brittle failure of the site are introduced. Various evaluation and measures are sought to stabilize the over-stressed rock mass. The major results from numerical analysis of the cavern are presented, and from current microseismic monitoring to detect hazard from brittle failure are presented.