• Geophysics and Geophysical Exploration
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• v.21 no.3
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• pp.139-149
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• 2018

The resistivity monitoring is a practical method to resolve changes in resistivity of underground structures over time. With the advance of sophisticated automatic data acquisition system and rapid data communication technology, resistivity monitoring has been widely applied to understand spatio-temporal changes of subsurface. In this study, a new 4D inversion algorithm is developed, which can effectively emphasize significant changes of underground resistivity with time. To overcome the overly smoothing problem in 4D inversion, the Lagrangian multipliers in the space-domain and time-domain are determined automatically so that the proportion of the model constraints to the misfit roughness remains constant throughout entire inversion process. Furthermore, a focusing model constraint is added to emphasize significant spatio-temporal changes. The performance of the developed algorithm is demonstrated by the numerical experiments using the synthetic data set for a time-lapse model.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.656-668
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• 2008

When it comes to design and acquire underwater vehicles such as a submarine and a torpedo according to the process of SBA(Simulation Based Acquisition)/SBD(Simulation Based Design), it is necessary to predict the performance of interest precisely and to perform the test over and over again using the M&S(Modeling and Simulation) of the engineering and the engagement level. In this paper, we research the DEVS(Discrete Event System Specification) and DTSS(Discrete Time System Specification) formalism based standard model architecture for the underwater vehicle which can support both the heterogeneous level of the M&S(Engineering/Engagement) and the different system of the M&S(Discrete Event System and Discrete Time System). To validate this standard modeling architecture, we apply it to the submarine normal diving simulation.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.1-16
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• 2005

When Web-based special retrieval systems for scientific field extremely restrict the expression of user's information request, the process of the information content analysis and that of the information acquisition become inconsistent. Accordingly, this study suggests the re-ranking retrieval model which reflects the content based similarity between user's inquiry terms and index words by grasping the document knowledge structure. In order to accomplish this, the former constructs a thesaurus and similarity relation matrix to provide the subject analysis mechanism and the latter propose the algorithm which establishes a search model such as query expansion in order to analyze the user's demands. Therefore, the algorithm that this study suggests as retrieval utilizing the information structure of a retrieval system can be content-based retrieval mechanism to establish a 2-step search model for the preservation of recall and improvement of accuracy which was a weak point of the previous fuzzy retrieval model.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1038-1043
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• 2015

When the study on the relationship between the Head-of-Bed (HOB) angle and ventilator-associated pneumonia is performed, the fact that the HOB angle can only be measured intermittently imposes a significant limitation on the study. Therefore, there has been demand for the development of a device that can measure the HOB angle continuously. In this paper, we propose the rapid prototyping of an HOB measurement system using open-source hardware and software. The proposed system helps to maintain the HOB angle at a particular angle by displaying the angle and helps the medical study of pneumonia patients by enabling continuous data acquisition. Firstly, we eliminate the process of making an MCU board by utilizing an open-source hardware mbed LPC1768. Secondly, we reduce the software development time by using libraries and hence enabling the easy use of peripherals. Thirdly, for rapid prototyping, we build the enclosure of the proposed system using a 3D printer. The proposed system can be attached and detached to and from a bed. Therefore, we can attach it to the bed of a patient for whom measurement of the HOB angle is necessary. Finally, we check the measurement performance and the validity of the proposed system through an experiment utilizing an incremental encoder.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.6 s.360
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• pp.24-30
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• 2007

In this paper, an energy detection-based low power, low complexity IR-UWB receiver in multipath impulse radio channel is presented. The proposed receiver has a simple 1-bit sampler for energy detection. Also, multipath signal received from multipath impulse radio channel is amplified and envelope of the signal is detected. Then, energy detection technique using integrator by summing multipath signals in certain period is adopted to minimize the BER loss by simple energy detection. In particular, in acquisition of a sample signal, SNR is additionally improved using a digital sampler. Symbol decision using several sampled signals is performed and thus the process of symbol synchronization is significantly simplified. Also, it is effectively designed to be compatible with influences of multipath and timing error. In addition, the proposed receiver complexity is reduced using pulse decision window. The performance of the proposed receiver is simulated based on IEEE 802.15.4a channel model and the algorithms are implemented on FPGA.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.832-835
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• 2007

The purpose of this study is to suggest the on-the-spot survey method of road occupation information. The on-the-spot survey method is proposed through the analysis of information searching function, document and process. The decision of road occupation permission and the grasp of illegal occupation status are closely connected with national rights and interests. To keep the road occupation permission and illegal occupation status, the easy acquisition of road occupation information is very important. But the person in charge of road occupation have a difficulty in obtaining occupation information because that information is still managed by paper drawing. Accordingly. this study develop the on-the-spot survey tool of road occupation using the occupation information that is managed by Construction Authorization & Permission System and the mobile techniques like UMPC. As the result of this study. the efficiency on the authorization. permission. and public grievance of construction project has improved

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.768-773
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• 2007

Standardization to information attribute of construction material is continuous demanded through the life cycle of a construction project, and the productivity elevation is derived of contribution effect in construction market. This study surveyed the means of acquisition and attribute of information to a staff in purchase, which are effected on the revitalization of information circulation to the construction material Proposed the standardization to information attribute of construction material that is based on improvement and application to the information attribute. And information attribute is classified with construction process through analysis on test list of quality certification. This study also suggested representative attribute of quality information, for the elevation of safety and quality in construction industry. Therefore, logicality of common information is based by analysis of mathematical statistics, systemicity of quality information is applied by MasterFormat(2004)

• Journal of Technologic Dentistry
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• v.34 no.3
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• pp.213-220
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• 2012

Purpose: The aim of this study was to determine the repeatability and reproducibility of two dental scanners. Methods: The master die and the stone replicas(Kavo, Germany) were digitized in touch-probe scanner(Incise, Renishaw, UK), white light scanner(Identica, Medit, Korea) to create 3-dimensional surface-models. The number of points in the point clouds from each reading were calculated and used as the CAD reference model(CRM). Discrepancies between the points in the 3-dimensional surface models and the corresponding CRM were measured by a matching-software(Power-Inspect R2, Delcam Plc, UK). The t-student test for one samples were used for statistical analysis. Results: The reproducibility of both scanner was within $3{\mu}m$, based on mean value. The mean value between measurements made directly on the touch probe scanner digital models and those made on the white light scanner digital models was $2.20-2.90{\mu}m$, and was statistically significant(P<0.05). Conclusion: With respect to adequate data acquisition, the reproducibility of dental scanner differs. Three-dimensional analysis can be applied to differential quality analysis of the manufacturing process as well as to evaluation of different analysis methods.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.65-70
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• 2012

Experimental investigations were carried out to examine the explosion characteristics by different sizes in the wall surface shape of a water gel barrier in an explosion chamber, 1,600 mm in length with a square cross-section of $100{\times}100\;mm^2$. The sizes in the wall surface shape were varied by using water gel barriers with a cross-section of $100{\times}200\;mm^2$ and its were varied in the bottom of the chamber away 300, 700 and 1,100 mm, respectively from the closed end of the chamber. The flame propagation images were photographed with a high speed camera and the pressure was recorded using a pressure transducer and a data acquisition system. It was found that as the size of the wall surface shape increased, the flame propagation process and the time taken to reach the maximum pressure were found to be faster. As a result, both the flame speed and the explosion overpressure increased as the size of the wall surface shape increased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.317-323
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• 1998

A synchronization is important element not only wire communication but also wireless communication. Especially, In SS(Spread Spectrum) communication method used GPS(Global Positioning System) synchronization is more important. A synchronous oscillator(SO) is a network which synchronizes, tracks, filter, amplifies and divides (if necessary) in a single process. Without an input signal, the SO is a free-running oscillator, oscillating at a frequency $w_0$, but phase changes $180^{\circ}$ within tracking range of SO. Therefore CPSO was used for this problem. The coherent phase synchronous oscillator(CPSO) is created by adding two external loops to the SO and has a wider tracking bandwidth and a zero-offset phase response (coherent) while maintaining the SO properties of high signal-to-rejection and fast frequency acquisition times. Therefore phase between input signal and output signal is synchronized. In this paper, GPS data recovery circuit has applied CPSO using front reference characters and has certified an excellent data recovery capability.