• Tunnel and Underground Space
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• v.21 no.1
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• pp.1-10
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• 2011

In these days, the development of optical fiber sensor technology is so remarkable that it can measure various physical and chemical quantities ranging from a few millimeters to over several kilometers. In addition, it is attempted to assess the structural integrity of the state of the advanced technologies and existing structures such as ships, aircrafts, and bridges. This paper introduced the case histories of the measuring technology of optical fiber applied on structures such as roads and tunnels. The case history using OTDR (Optical Time Domain Reflectometery) was also introduced in this paper. Measurement of the pre-convergence of a tunnel is essential to assess the safety of a tunnel and understand the geological conditions ahead of an advancing tunnel. Therefore, the pre-convergence measuring technology using OTDR is expected to substitute conventional measuring techniques.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.3
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• pp.229-236
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• 2000

This paper proposes on the Hanguel character CAI system using image processing. For this, firstly, the characters written by elementary school students or foreigners arc captured by CCD camera. Secondly, Recognition is accomplished by pre-processing, thinning and recognition processes. Thirdly, strokes are separated and beauty evaluation is done by matching feature value of the input image from the similarity measure function. In particular, this paper describe to define the similarity measuring function using extracted factor values after getting the beauty evaluation factor values of the consonant in the entire CAI system. Finally, the effectiveness of the proposed system is demonstrated by experiments.

• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.89-96
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• 2016

In mobile communication, there are various types of handoff for the support of all forms of mobility. Proxy mobile IPv6 (PMIPv6) enables local network-based mobility management of a mobile node without any effect of mobility-related signaling. Recently, PMIPv6 has been considered for supporting mobility management in LTE/SAE-based mobile networks. To support seamless mobility in heterogeneous mobile networks, the overall cost of handoffs needs to be minimized and the procedure should be guaranteed to be secure. However, the reduction of the authentication cost has not been fully investigated to provide seamless connectivity when mobile users perform a handoff between the PMIPv6 domains. This paper proposes secure pre-authentication schemes, completing an authentication procedure before performing a handoff, for a fast handoff in PMIPv6. Analytic models have been used for measuring the authentication latency and for the overhead cost analysis. In addition to providing fast authentication, the proposed pre-authentication schemes can prevent threats such as replay attacks and key exposure.

• Communications for Statistical Applications and Methods
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• v.30 no.1
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• pp.37-48
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• 2023

Shape analysis is a method for measuring, describing and comparing the shape of objects in geometric space. An important aspect is to obtain Procrustes distance based on least square method. We note that the shape is all the geometrical information that remains when location, scale and rotational effects are filtered out from an object. However, and unfortunately, when we cannot measure some landmarks which are some biologically or geometrically meaningful points of any object, it is not possible to measure the variation of all shapes of an object, including that of the incomplete object. Hence, we need to replace the missing landmarks. In particular, Albers and Gower (2010) studied the missing rows of configurations in Procrustes analysis. They noted that the convergence of their approach can be quite slow. In this study, alternatively, we derive an algorithm for estimating the missing landmarks based on the pre-shapes. The pre-shape is invariant under the location and scaling of the original configuration with the centroid size of the pre-shape being one. Therefore we expect that we can reduce the amount of total computing time for obtaining the estimate of the missing landmarks.

• Journal of the Korean earth science society
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• v.36 no.5
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• pp.484-499
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• 2015

This study explores the impact of a STEM integration teacher professional development program focusing on teachers' perception of engineering and their attitudes toward integrating engineering into teaching. A total of sixty-eight teachers from ten schools participated in the program for five days. Data are collected from three main sources including (1) pre and post concept maps probing teachers' perceptions about the engineering discipline, (2) a pre and post survey measuring teachers' self-efficacy of teaching science/mathematics within the engineering context, and (3) engineering integrated science and (or) mathematics lesson plans and teaching reflections. This study utilizes both qualitative and quantitative research methods depending on the data we have collected. The results show that both science and math teachers thought that integrating engineering into teaching provided valuable outcomes, i.e., promoting students' learning about engineering and improving their interest in science or math through real-world problem solving exercises. Participants also felt more comfortable about integrating engineering in their teaching after the program. The results also imply that the teachers' understandings of engineering become more concrete after the program. This study also provides an overview of the challenges and advantages of teaching engineering in K-12 science and mathematics classrooms.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2006.06a
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• pp.97-100
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• 2006

A sensor and measuring system were implemented to measure both uroflow and urophonography signal during urination for diagnose the BPH(benign prostatic hypertrophy). The implemented system was composed of the uroflow sensor using the load-cell, the urophonography measurement sensor so as stethoscope type, pre-processing part for sensors signal detection, amplifier and filter, system control parts and PC measurement program. A simulator of the lower urinary system that is experimental equipment implemented for evaluates the developed system. The two signals were measured using implemented system and analyzed these signal by means of time domain and frequency domain for extraction of the characteristic parameter which can most effectively reflected by the occlusion of the lower urinary system. Furthermore two signals were measured and analyzed with the subject of 5 healthy adult for clinical application possibility of the implemented system. As a result, the most influence bandwidth of effect according to occlusion of the lower urinary system is $253{\sim}282Hz$ of the urophonography signal.

• Textile Coloration and Finishing
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• v.29 no.2
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• pp.86-96
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• 2017

To make uniform pressure distributed over the contact surface was necessary to cold pad batch dyeing machine. In this study, to confirm characteristic of flexibility and the contact pressure distribution through experimental analysis of padder roll were controlled by hydraulic cell. When there were no load pressure only inner pressure, the value of displacement in the center of padder were greater than the end of the padder. The results of this study showed that the padder had the optimum value of inner pressure for uniform contact pressure distribution. Measuring the contact pressure in a padder system were driven by using a pre-scale film. Uniform contact pressure distribution of cell padder were a linearly with load pressure and inner pressure. When the load pressure was less than 8 tons, the inner pressure for the uniform contact pressure was 1~4 bar. The padder roll performance curves proposed in this study were available for practical production environments and various roll designs.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.141-148
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• 2019

The advancement of digital technology accelerates intelligence, convergence, and demands better change beyond traditional methods in all aspects of business models and technologies, infrastructure, processes, and platforms. Risk management is becoming more important because of various security risks, depending on the changing business environment and aligned to business goals is emerging from the existing information asset based risk management. For business aligned risk management, it is essential to understand the risk appetite for achieving business goals, which provides a basis for decision-making in subsequent risk management processes. In this paper, we propose a framework for analyzing the risk management framework, pre - existing risk analysis, and protection motivation theory that influences decisions on security risk management. To examine the practical feasibility of the developed risk appetite framework, we reviewed the applicability and significance of the proposed risk appetite framework through an advisory committee composed of security risk management specialists.

• Journal of Digital Convergence
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• v.10 no.8
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• pp.317-326
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• 2012

The study aims at analyzing and comparing the effect of video teleconferencing English class with native speakers on class satisfaction and self-efficacy of elementary school students according to grades. Revised Kim's self efficacy and researcher's class satisfaction measuring tools were used for this. Grade 3 got the highest score and grade 6 had the lowest one in class satisfaction. In post-testing on self efficacy, average score was lower than in pre-testing except grade 3. Grade 3 got the highest score and grade 6 had the lowest one in self efficacy. I conclude that as students' grade goes up, their interests decrease in teleconferencing class and native speaker teachers.

• Journal of Power Electronics
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• v.8 no.3
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• pp.217-227
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• 2008

The electric power subsystems (EPS) of most remote sensing satellites consist of a solar array as a source of energy, a storage battery, a power management and control (PMC) unit and a charge equalization unit (CEU) for the storage battery. The PMC and CEU use high frequency transformers in their power modules. This paper presents a design, implementation and testing results of a high frequency transformer for the EPS of satellite applications. Two approaches are used in the design process of the transformer based on the pre-determined transformer specifications. The transformer is designed based on an ETD 29 ferrite core. The implemented transformer consists of one center-tapped primary coil with eleven center-tapped secondary coils. The offline calculation results and measured values of R, L for transformer coils are convergence. A test circuit for measuring the transformer parameters like voltage, current and B-H hysteresis was implemented and applied. The test results confirm that the voltage waveforms of both primary and secondary coils were as desired. No overlapping occurred between the control signal and the transformer, which was not saturated during testing even during a short circuit test of the secondary channels. The dynamic B-H loop characteristics of the used transformer cores were measured. The sample test results are given in this paper.