• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.73-82
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• 2004

This paper presents the study on damage diagnosis of an intelligent cantilevered beams using PZT actuator and PVDF sensor This study provides the theoretical and experimental verification to examine structural damage. Time domain analysis for the non-destructive detection of damage is presented by parameterized partial differential equations and Galerkin approximation techniques. The time histories of the vibration response of structure were used to identify the presence of damage. Furthermore, this systematic approach permits one to use the piezomaterials to both excite and sense the vibration of structures. We also carried out the experimental verification about reliability of theoretical methods fur detecting the damage of a composite beam with PZT actuator and PVDF sensor. Experimental results are presented from tests on cantilevered composite beams which is damaged at different location and different dimensions. The results were compared with the simulation results. Good agreement between the results was found for the time shifts and amplitude difference in transients response of the cantilevered beam.

• Journal of Navigation and Port Research
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• v.45 no.5
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• pp.231-237
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• 2021

Enhancing the performance of maritime wireless communication has been highlighted by the issue of cell planning in the sea area because of lack of an appropriate Propagation Loss Model (PLM). To resolve the cell planning issue in vast sea areas, it was essential to develop the (PLM) matching the intended sea area. However, there were considerable gaps between the prediction of legacy PLMs and field measurement in propagation loss and there was a need to develop the adjusted PLM (A-PLM). Therefore, cell planning was performed on this adjusted model, including modification of the base station's location, altitude, and antenna azimuth to meet the quality objectives. Furthermore, in order to verify the availability of the cell planning, Communication Service Quality Monitoring System (CS-QMS) was developed in the LTE-Maritime project to collect LTE signal quality information from the onboard equipment at regular intervals and to ensure that the service quality was high enough to satisfy the goals in each designated grid. As a result of verification, the success rate of RSRP was 95.7% for the intensive management zone (IMZ) and 96.4% for the interested zone (IZ), respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.2
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• pp.165-174
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• 2021

This study describes a method of measurement and verification of array manifold of uniform circular array antenna applicable to multistatic Passive Coherent Location(PCL) system using FM broadcasting. In an environment of outdoor test where FM broadcast signals are scattered, array manifold measurement methods using network analyzer and multi-channel digital receiver are introduced. Also, the descriptions and solutions for the test limits of each measurement method and the considerations affecting the measurement accuracy are presented. In addition, to verify the validity of the measured array manifold, the gain and phase difference were compared with the array manifold data obtained by EM simulation, and the effectiveness and accuracy of the measured array manifolds were compared and analyzed by estimating the direction of arrival of the FM broadcast signal received from the multistatic PCL system.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1813-1824
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• 2022

This paper shows the verification work of SARAX code system in the reactor core transient calculation based on the simplified EBR-II Benchmark. The SARAX code system is an analysis package developed by Xi'an Jiaotong University and aims at the advanced reactor R&D. In this work, a neutron-photon coupled power calculation model and a spatial-dependent reactivity feedback model were introduced. To verify the models used in SARAX, the EBR-II SHRT-45R test was simplified to an ULOF transient with an input flowrate change curve by fitting from reference. With the neutron-photon coupled power calculation model, SARAX gave close results in both power fraction and peak power prediction to the reference results. The location of the hottest assembly from SARAX and reference are the same and the relative power deviation of the hottest assembly is 2.6%. As for transient analysis, compared with experimental results and other calculated results, SARAX presents coincident results both in trend and absolute value. The minimum value of core net reactivity during the transient agreed well with the reported results, which ranged from -0.3$ to -0.35$. The results verify the models in SARAX, which are correct and able to simulate the in-core transient with reliable accuracy.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.87-94
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• 2023

This study analyzed and identified various causes of caustic alarms of 163 fire detectors that occurred from January 2019 to December 2021 at domestic semiconductor manufacturing plants equipped with about 30,000 fire detectors, and proposed a new non-fire prevention cause investigation plan by applying the NFPA 921 scientific methodology. The results of the study are as follows. First, in terms of necessary recognition and problem definition, an analog detector and an integrated monitoring system were proposed to quickly determine the location and installation space information of the fire detector. Second, in order to prevent speculative causes and errors in various analyses in terms of data analysis and hypothesis establishment, non-fire reports were classified into five by factor and defined, and the causes of occurrence by factor were classified and proposed. Finally, in terms of hypothesis verification and final hypothesis selection, a non-fire prevention improvement termination process and a final hypothesis verification sheet were proposed to prevent the cause from causing re-error.

• Journal of the Korea Society of Computer and Information
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• v.15 no.10
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• pp.27-34
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• 2010

This paper proposes an efficient method for verifying palmprint which is captured at the natural interface without any physical restriction. The location and orientation of the region of interest (ROI) in palm images are variously appeared due to the translation and rotation of hand. Therefore, it is necessary to extract the ROI stably for palmprint recognition. This paper presents a method that can extract the ROI, which is based on the reference points that are located at the center of the crotch segments between index finger and middle finger and between ring finger and little finger. It also proposes a palmprint recognition method using the histogram of local binary patterns (LBP). Experiments for evaluating the performance of the proposed method were performed on 1,597 palmprint images acquired from 100 different persons. The experimental results showed that ROI was correctly extracted at the rate of 99.5% and the equal error rate (EER) and the decidability index d' indicating the performance of palmprint verification were 0.136 and 3.539, respectively. These results demonstrate that the proposed method is robust to the variations of the translation and rotation of hand.

• Journal of Industrial Technology
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• v.30 no.B
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• pp.125-135
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• 2010

The influences on water quality of each river by effluents from environmental facilities $located^{*}$ in 14 unit watersheds of North- and South-Han River, and Gyungan-cheon were analyzed. Also, the water quality modeling for study area was carried out to analyze the improvement effect of water quality by the strengthening of T-P effluent standard of environmental facilities. For the calibration and verification of model, water quality data and effluent loading calculated for 2006 were used. Data of low water period were used for calibration, and normal water period for verification. The results of calibration and verification were well matched with the real water quality dataset of revers. Also, the validity of the results were estimated using RI (Reliability Index) method. When the T-P effluent standards for environmental facilities were strengthened, T-P concentrations were predicted to improve from $0.025mg/{\ell}$ to $0.023mg/{\ell}$ in the outlet location of North-Han River, from $0.056mg/{\ell}$ to $0.040mg/{\ell}$ for South-Han River,and from $0.233mg/{\ell}$ to $0.146mg/{\ell}$ for Gyungan-cheon. Also, the T-P concentrations of tributaries including Jojong-cheon, Dal-cheong, Sumgang, Chungmi-cheon, Bokha-cheon, Heuk-cheon, and Wonju-cheon were predicted to improve from $0.063mg/{\ell}$ to $0.010mg/{\ell}$, from $0.091mg/{\ell}$ to $0.053mg/{\ell}$, from $0.199mg/{\ell}$ to $0.100mg/{\ell}$, from $0.168mg/{\ell}$ to $0.148mg/{\ell}$, from $0.186mg/{\ell}$ to $0.105mg/{\ell}$, from $0.019mg/{\ell}$ to $0.013mg/{\ell}$, and from $0.822mg/{\ell}$ to $0.236mg/{\ell}$, respectively.

• The Journal of the Korea Contents Association
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• v.19 no.9
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• pp.476-484
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• 2019

RFID yoking proof proves that a pair of tags is scanned at the same time. Since the tags scanned simultaneously by a single reader are adjacent to each other, the yoking proof is used in applications that need to check the physical proximity of tagged objects. Most of the yoking proof schemes require pre-knowledge on adjacent tags. If an error occurs in the process of collecting information about adjacent tags, all subsequent proofs will fail verification. However, there is no research that suggests specific methods for obtaining information about adjacent tags. In this study, I propose a tag proximity information acquisition scheme for a yoking proof. The proposed method consists of two steps: scanning area determination and scanning area verification. In the first step, the size and position of the area to scan tags is determined in consideration of position and transmission range of the tags. In the next step, whether tag scanning is performed within the scanning area or not is verified through reference tags of the fixed position. In analysis, I show that the determined scanning area assures acquisition of adjacent tag information and the scanning area verification detects deformation and deviation of the scanning area.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.161-167
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• 2010

To realize the U-healthcare system, the mobile patient monitoring system is of the essence. In this monitoring system, a patient's real-time data on biometrics and location must be transferred to predeterminate destination server ceaselessly. As the number of mobile patients increases steadily or mobile patients are moving into some specific area, the load balancing solution to real-time data congestion problem is needed. In this paper, we propose a new mobile patient monitoring system with Torus topology where three layers are connected hierarchically and the intermediate layer takes charge of priority-based load balancing. For the formalized design and verification of proposed system, we describe the overall structure with connectivity among its components and implement major components in pseudo-code by adopting a system specification-based approach. This approach makes the design and verification of our mobile patient monitoring system more flexible and accurate.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.1
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• pp.14-20
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• 2015

In this study, we propose an innovative lateral force distribution building system between tall buildings by utilizing the difference of moment of inertia, as the alternative design for highly integrated city area. Considering a tri-axial symmetric conditions and boundary conditions for the three-dimensional building structure system, a two-dimensional model is composed. In the proposed indeterminate structural model, important design variables are determined for obtaining minimum horizontal deflections, reactions and bending moments at the ground level of the buildings. Regarding a case of the provided two spatial structures connected to 4 buildings, the optimum location of middle located spatial structure is 45% from the top of the building, which minimize the end moments at the bottom of the buildings. In the considered verification examples, reduced drifts at the top location of the building systems are validated against static wind pressure loads and static earthquake loads. The suggested hybrid building system will improve the safety and reliability of the system due to the added internal truss-dome structures in terms of more than 30% reduced drift and vibration through the development of convergence of tall buildings and spatial structures.