• Proceedings of the Korean Geotechical Society Conference
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• 2000.03c
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• pp.1-36
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• 2000

Construction incidents, mechanisms and causes in Geotechnical Engineering have been closely reviewed for the safety assurance during design and construction stages. The safety assurance is clearly related to the observational method in which design is reviewed during construction and contingency actions are undertaken successfully to minimise any potential failures. The observational method has been extensively applied for the construction of subways underground structures, dams and many important Civil Engineering projects in the past 20 years. But the number of serious construction incidents are growing for the past several decades. Therefore present development of observational method and improvement techniques are introduced with some case histories.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.10a
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• pp.37-48
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• 1997

• Journal of Astronomy and Space Sciences
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• v.36 no.3
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• pp.187-197
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• 2019

The Optical Wide-field patroL-Network (OWL-Net) is a Korean optical space surveillance system used to track and monitor objects in space. In this study, the characteristics of four Initial Orbit Determination (IOD) methods were analyzed using artificial observational data from Low Earth Orbit satellites, and an appropriate IOD method was selected for use as the initial value of Precise Orbit Determination using OWL-Net data. Various simulations were performed according to the properties of observational data, such as noise level and observational time interval, to confirm the characteristics of the IOD methods. The IOD results produced via the OWL-Net observational data were then compared with Two Line Elements data to verify the accuracy of each IOD method. This paper, thus, suggests the best method for IOD, according to the properties of angles-only data, for use even when the ephemeris of a satellite is unknown.

• Journal of the Ergonomics Society of Korea
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• v.22 no.1
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• pp.43-56
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• 2003

Observational methods such as OWAS, RULA, and REBA have been widely used to identify posture-related risks of musculoskeletal disorders in industry, since they are useful and efficient in evaluating postural stresses. However. there are few studies comparing the methods and providing guidelines for selecting and using the methods. They have been developed based on different backgrounds and with different application areas. Each method has its own characteristics. which must be considered in selecting and using them. In this study. 17 male subjects evaluated 42 different working postures that frequently assumed in the automobile assembly line using a psychophysical method. The postures were then evaluated by different observational methods. The results of the observational methods were compared with psychophysically evaluated stresses. The observational methods resulted in different values of stresses for certain postures. For some postures showing high values of perceived discomfort. the observational methods showed different values of stresses. These results showed that the observational methods should be used differently according to application area and they have some weak points to be improved.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.147-179
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• 2002

The important role of observational method in geotechnical engineering are emphasized together with the direction of future development, concerning successful application of the technique on the site investigation, design and feed back at various construction stages. Case histories on the application of feed back are introduced in order to achieve the most economical and reliable construction for tunnel, rock slope and deep excavations through feed back system at design and construction stages. Also the limitations and advantages of the observational method and the role of feed back system are discussed for construction of tunnel, rock slope and deep excavation in hard ground such as layered ground conditions including weathered, soft and hard rocks.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.1-10
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• 2006

Rock masses in nature include various rock discontinuities such as faults, joints, bedding planes, fractures, cracks, schistosities, and cleavages. The behavior of rock structures, therefore, is mainly controlled by various rock discontinuities. In many tunnels, enormous cost and time are consumed to cope with the failing or sliding of rock blocks, which cannot be predicted because of the complexity of rock discontinuities. It is difficult to estimate the properties of rock masses before the rock excavation. The observational design and construction method of tunnels in rock masses is becoming important recently. In this paper, a new observational design and construction method for rock block evaluation of tunnels in discontinuous rock masses is proposed, and then applied to the tunnel based on actual rock discontinuity information observed in the field. It is possible to detect key blocks all along the tunnel exactly by using the numerical analysis program developed far the new observational design and construction method. This computer simulation method with user-friendly interfaces can calculate not only the stability of rock blocks but also the design of supplementary supports. The effectiveness of the proposed observational design and construction method has been verified by the confirmation of key block during the enlargement excavation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.3
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• pp.275-283
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• 2010

Recently, the observational design and construction method in tunnels has been becoming important. Rock masses include various discontinuities such as joints, faults, fractures, bedding planes, and, cracks. The behavior of tunnels in hard rocks, therefore, is generally controlled by various discontinuities. In this study, a new key block analysis method for observational design and construction method in tunnels is proposed, and then applied to the actual tunnel with a super-large cross-section. The proposed analysis method considers finite persistence of discontinuities. The new analysis method can handle concave and convex shaped blocks. To demonstrate the applicability of this key block analysis method for observational design and construction method in tunnels, the analysis results are examined and compared with those of the conventional method.

• Journal of Korean Academy of Nursing
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• v.27 no.4
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• pp.892-900
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• 1997

The purpose of this study was to use phenomenological perspectives to identify the meaning and structure of the observational experience of labor and delivery by student nurses in the clinical setting. The participants were 115 junior and senior students from Christian College of Nursing in Kwang Ju. The students were asked to write about their observational experience in the delivery room. Colaizzi's method was used for phenomenological analysis. The investigator analysed the data to identify and categorize themes and basic structural elements. Twelve themes and eight basic structure were identified. The process of the observational experience in labor and delivery has three proposed phases : anticipatory, observational and post-observational. In the anticipatory phase, nursing students were related only to the event of anticipated labor and delivery of clients. Structure 1, feeling of expectation and fear, was identified. In the observational phase, students were related to the labor and delivery situation, a woman delivered and a newborn. Structure 2, shock and suffering, was identified in relation to the labor and delivery situation. Structure 3, need for caring and satisfaction, was identified in relation to the woman delivered. Structure 4, feeling of mystery and joy, was identified in relation to the newborn. In the post-observational phase, relations between students and the life of a human being, students and self in the future, students and their mothers and students and women and God appeared. And in these relations 〈structure 5, valuable〉, 〈structure 6, feeling of expectation and fear〉, 〈structure 7, love and appreciation〉 and 〈structure 8, greatness〉 were identified.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03c
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• pp.37-54
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• 2000

The observational method using field measurement technique have contributed significantly to advancements in the state-of-the art of geotechnical engineering in the 20th century. Due to the rapid development in computer technology, Internet and GIS have become an integral part of civil engineering project management. This paper presents new technologies and development in observational method which have valuable implication on field measurement in geotechnical engineering. Systematic approach to planning monitoring program in geotechnical instrumentation is also presented. Finally, research needs in development and application of integrated design/construction management system in geotechnical engineering projects are discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.140-150
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• 2003

Observational methods such as the Asaoka's method and the hyperbolic method are widely applied on the settlement analysis using observed settlement. The most unreliable aspects in those methods is arose from the subjective discretion of initial non-linearity on linear regression. The initial non-linearity is inevitable due to the settlement behaviour itself. Therefore an objective method is essential to achieve more reliable results on settlement analysis. It was found that the initial non-linear data are statistical outliers. New automation algorithms of the hyperbolic and the Asaoka's method were developed based on outlier detection method. The methods are a successive detection of outliers and a searching method of suitable hyperbolic range for the Asaoka's and the hyperbolic method respectively. Applicability of the algorithms was verified through case studies.