• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.207-218
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• 2013

One of the input parameters in the evaluation of seismic performance of rockfill dams is shear-wave velocity of rock debris and clay core. Reliable evaluation of shear-wave velocity by surface-wave methods requires overcoming the problems of rock-debris discontinuity, material inhomogeneity and sloping boundary. In this paper, for the shear-wave velocity investigation of rockfill dams, SBF (Short-Array Beamforming) technique was proposed using the principles of conventional beamforming technique and adopted to solve limitations of the conventional surface-wave techniques. SBF technique utilizes a 3- to 9-m long measurement array and a far-field source, which allowed the technique to eliminate problems of near-field effects and investigate local anomalies. This paper describes the procedure to investigate shear-wave velocity profile of rockfill dams by SBF technique and IRF (Impulse-response filtration) technique with accuracy and reliability. Validity of the proposed SBF technique was verified by comparisons with downhole tests and CapSASW (Common-Array-Profiling Spectral-Analysis-of-Surface-Waves) tests at a railroad embankment compacted with rock debris.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.98-100
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• 1989

Langmuir-Blodgett(LB) technique will be used to produce ultra thin film, and then characterization of the physical and electrical properties of LB ultra thin films, this study will be an investigation for the possibilities of the ultra thin films as an Molecular Electronic Device.

• The Journal of Engineering Geology
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• v.12 no.2
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• pp.179-188
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• 2002

With improving computer penormance and advancing simulation techniques, a growing number of softwares are being developed for visualization of investigation results in geotechnical problems. It is a very important subject for geological site investigation to understand or predict if there would be any hazardous geological conclition that might cause any increase of construction costs or an extension of construction period. A 3-D (three-climensional) visualization technique may be one of the powerful tools to overcome an uncertainty problem of geologica] site investigatior. The paper describes an overview of a newly developed geotechnical 3-D interpretation system for the purpose of applying the 3-D visualization technique, GIS (geographic information system) and D/B (database) to tunnel design and construction. VR (virtual reality) and 3-D visualization techniques are applied in order to develope the 3-D model of characteristics and structures of rock mass. D/B system for all the materials related to site investigation and tunnel construction is developed using GIS technique. This system is very useful for civil engineers to make a plan of tunnel construction at the design stage and also during construction with the advantage of improving the economy and safety of tunnels.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.1
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• pp.311-324
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• 2022

The objective of this study is to examine the influence of fraud investigation on organizational performance of Thai listed companies through mediating effects of internal audit quality, accounting information transparency and financial effectiveness, and moderating effect of corporate governance. In this study, 333 Thai listed companies are the samples of the study. Both the structural equation model and multiple regression analysis are used to examine the research relationships. The results of this study show that fraud investigation has a significant influence on internal audit quality, accounting information transparency, and financial effectiveness. Internal audit quality significantly influences accounting information transparency, financial effectiveness, and organizational performance while financial effectiveness significantly influences organizational performance. Next, both internal audit quality and financial effectiveness potentially mediate the fraud investigation-organizational performance relationships. In addition, corporate governance critically moderates the fraud investigation-internal audit quality relationships and the fraud investigation-financial effectiveness relationships. In summary, fraud investigation functions as an important valuable technique of internal audit practices. As a result, businesses must build and implement a systematic fraud investigation procedure to generate and improve beneficial outcomes in the short, medium, and long term.

• Journal of Welding and Joining
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• v.20 no.5
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• pp.29-35
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• 2002

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.696-699
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• 2004

A side scan sonar system uses the towfish installed sonars, It is an equipment that search images of the bottom surface of the sea in real time. It is a typical equipment that is related to a sea investigation such as a geological survey, seabed communication cable and power line cable placing repair investigation, fish breeding ground investigation, sea purification, relic and mineral investigation, and mine and submarine search. It used to fined objects and investigate on the seabed surface. But, recently, it is used to sea purification and geological survey that require information of the correct surface of the seabed. So, it needs various filtering technique and image processing techniques development to acquire high resolution image. therefore, this research develops a side scan sonar using multi-beam sensors that supply various information with the fast scan speed and correct high resolution that is not a simple underwater investigation equipment.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.317-318
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• 2006

The towfish oi a side scan sonar is an equipment that search images of the bottom surface of the sea in real time. It is a typical equipment that is related to a sea investigation such as a geological survey, seabed communication cable and power line cable placing repair investigation, fish breeding ground investigation, sea purification, relic and mineral investigation, and mine and submarine search. It used to find objects and Investigate on the seabed surface. But, recently, it is used to sea purification and geological survey that require information of the correct surface of the seabed. So, it needs various filtering technique and image processing techniques development to acquire high resolution image. Therefore, this research develops a side scan sonar using multi-beam sensors that supply various information with the fast scan speed and correct high resolution that is not a simple underwater investigation equipment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.705-708
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• 2010

In the paper, we have studied on algorithms for two-dimensional positioning based on GPS pseudorange Technique. First, the linearized state equation was mathematically derived based on GPS pseudorange technique. Second, the geometry model with respect to triangles formed using unit-vectors were proposed for investigation of land-based radio positioning. Finally, the corresponding mathematical formulations for DOP values and covariance matrix were designed for two-dimensional positioning.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.2
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• pp.95-104
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• 2017

As the technology in smart device is growing and Social Network Services(SNS) are becoming more common, the data which is difficult to be processed by existing RDBMS are increasing. As a result of this, NoSQL databases are getting popular as an alternative for processing massive and unstructured data generated in real time. The demand for the technique of digital investigation of NoSQL databases is increasing as the businesses introducing NoSQL database in their system are increasing, although the technique of digital investigation of databases has been researched centered on RDMBS. New techniques of digital forensic investigation are needed as NoSQL Database has no schema to normalize and the storage method differs depending on the type of database and operation environment. Research on document-based database of NoSQL has been done but it is not applicable as itself to other types of NoSQL Database. Therefore, the way of operation and data model, grasp of operation environment, collection and analysis of artifacts and recovery technique of deleted data in HBase which is a NoSQL column-based database are presented in this paper. Also the proposed technique of digital forensic investigation to HBase is verified by an experimental scenario.

• Structural Engineering and Mechanics
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• v.51 no.1
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• pp.181-197
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• 2014

Stress determination is a very important step in the assessment of the safety of existing reinforced concrete structures. In rock mechanic this goal is achieved with the over-coring technique. The main idea behind such a technique is to isolate a material sample from the stress field in the surrounding mass and monitor its re-equilibrium deformation response. If the materials remains elastic, and elastic properties are known, stresses may be obtained from the corresponding measured strains. The goal of this paper is to evaluate if the over-coring technique is applicable to reinforced concrete members. The results of an experimental investigation on the behaviour of compressed concrete columns subjected to the over-coring technique are presented. Considerations about the range of applicability of the technique are made by comparing the measured and the theoretical stresses. After that, results of failure tests on drilled specimens are presented and discussed. Furthermore, the response is compared with that of columns core-bored before the compressive test. Finally, comparisons with numerical analysis are shown.