• Journal of the Korean Society of Safety
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• v.28 no.5
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• pp.21-26
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• 2013

Delamination of cover concrete due to re-bar corrosion is a critical damage reducing structural safety of reinforced concrete structures. Therefore, it should be detected and evaluated to provide appropriate maintenance to recover structural integrity. Impact-echo method, which utilizes thickness vibration characteristics of delaminated concrete section, is effective for detection and evaluation of small areal size delamination. However, it may not be applicable for large areal size delamination in which flexural vibration modes are dominated. In this study, applicability of vibration mode shapes of delaminated concrete section is investigated for visualization of delamination region in concrete structures. Numerical and experimental modal tests are performed to estimate mode shapes of delaminated concrete section and linear absolute summation technique is proposed for effective visualization of delamination region based on estimated mode shapes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1321-1327
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• 2014

Faulted section identification is one of the most important function in distribution automation systems. Conventional over current detection based fault indicators frequently mal-operate due to the reverse fault current from the renewable energy resources. This paper present a new faulted section identification method based on the fuzzy decision making technique. In order to establish feasibility of the proposed method, case studies using Matlab Simulink has been performed.

• ETRI Journal
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• v.45 no.2
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• pp.329-337
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• 2023

For safe last-mile autonomous robot delivery services in complex environments, rapid and accurate collision prediction and detection is vital. This study proposes a suitable neural network model that relies on multiple navigation sensors. A light detection and ranging technique is used to measure the relative distances to potential collision obstacles along the robot's path of motion, and an accelerometer is used to detect impacts. The proposed method tightly couples relative distance and acceleration time-series data in a complementary fashion to minimize errors. A long short-term memory, fully connected layer, and SoftMax function are integrated to train and classify the rapidly changing collision countermeasure state during robot motion. Simulation results show that the proposed method effectively performs collision prediction and detection for various obstacles.

• The KIPS Transactions:PartC
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• v.16C no.5
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• pp.555-562
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• 2009

In malware accident investigation, the most important thing is detection of malicious code. Signature based anti-virus softwares have been used in most of the accident. Malware can easily avoid signature based detection by using packing or encryption method. Because of this, packed file detection is also important. Detection methods can be divided into signature based detection and entropy based detection. Signature based detection can not detect new packing. And entropy based detection has a problem with false positive. We provides detection method using entropy statistics of entry point section and 'write' properties of essential characteristic of packed file. And then, we show packing detection tool and evaluate its performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.7
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• pp.732-737
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• 2016

A pulse radar signal exhibits periodic appearance of pulses in time. So it leads to a high correlation between two samples separated in time by multiples of its period. In this paper, we present a spectrum sensing technique for a radar signal which exploits the periodicity of its autocorrelation function and a radar pulse interval estimation scheme in order to address the case that the radar pulse interval is not known a priori. Finally, we evaluate the sensing performance of the proposed scheme through computer simulation and compare its performances with those of energy detection.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.266-271
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• 2014

The survivability of the naval ship is the capability of a warship to avoid or withstand a hostile environment. The survivability of the naval ship assessed by three categories (susceptibility, vulnerability and recoverability). The magnitude of susceptibility of a warship encountering with threat is dependent upon the attributes of detection equipment and weapon system. In this paper, as a part of a naval ship's survivability analysis, an assessment process model for the ship's susceptibility analysis technique is developed. Naval ship's survivability emphasizing the susceptibility is assessed by the probability of detection, and the probability of hit. Considering the radar cross section (RCS), the assessment procedure for the susceptibility is described. It's emphasizing the simplified calculation model based on the probability density function for probability of hit. Assuming the probability of hit given a both single-hit and multiple-hit, the susceptibility is accessed for a RCS and the hit probability for a rectangular target is applied for a given threat.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1699-1703
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• 2012

Cervical cancer remains the most frequent cancer in women from the developing world. More than 88% of deaths occur in low-income countries, and it is predicted to climb to 91.5% by 2030. Although Pap-based screening programmes have shown to be effective in reducing the disease burden in high-resource countries, implementation and sustention of cytology-based programmes is quite challenging in low-resource settings. The present paper reviews evidence-based alternatives of screening methods, triaging algorithm, treatment of cervical precancerous lesions, and age-group at screening appropriate for low-income countries. Evidence shows that visual inspection methods using diluted acid acetic or Lugol's iodine, and HPV-DNA testing are more sensitive tests than the Pap-smear screening test. Visual inspection allows an immediate result and, when appropriate, may be immediately followed by cryotherapy, the so called "screen-and-treat" approach, achieved in a single visit, by trained nurses and midwives. Examples of cervical cancer prevention programmes in India and selected low-income countries are given.

• Smart Structures and Systems
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• v.19 no.2
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• pp.181-194
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• 2017

In order to investigate the interface debonding defects detection mechanism between steel tube and concrete core of concrete-filled steel tubes (CFSTs), multi-physical fields coupling finite element models constituted of a surface mounted Piezoceramic Lead Zirconate Titanate (PZT) actuator, an embedded PZT sensor and a circular cross section of CFST column are established. The stress wave initiation and propagation induced by the PZT actuator under sinusoidal and sweep frequency excitations are simulated with a two dimensional (2D) plain strain analysis and the difference of stress wave fields close to the interface debonding defect and within the cross section of the CFST members without and with debonding defects are compared in time domain. The linearity and stability of the embedded PZT response under sinusoidal signals with different frequencies and amplitudes are validated. The relationship between the amplitudes of stress wave and the measurement distances in a healthy CFST cross section is also studied. Meanwhile, the responses of PZT sensor under both sinusoidal and sweep frequency excitations are compared and the influence of debonding defect depth and length on the output voltage is also illustrated. The results show the output voltage signal amplitude and head wave arriving time are affected significantly by debonding defects. Moreover, the measurement of PZT sensor is sensitive to the initiation of interface debonding defects. Furthermore, wavelet packet analysis on the voltage signal under sweep frequency excitations is carried out and a normalized wavelet packet energy index (NWPEI) is defined to identify the interfacial debonding. The value of NWPEI attenuates with the increase in the dimension of debonding defects. The results help understand the debonding defects detection mechanism for circular CFST members with PZT technique.

• Proceedings of the Korean Society of Computer Information Conference
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• 2009.01a
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• pp.211-214
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• 2009

Edge detection always influenced by noise belong to the original image, therefore need use some methods to sort this issue, mean shift algorithm has the smooth function which suit for the edge detection purpose, so adopted to fade out the unimportant information, and the sensitive noise portions. After this section, use the Canny algorithm to pick up the contour of the objects we focus on, meanwhile select the Soble operator that has the orientation attribute to support the method work well. In final, take experiment and get the perfect result we wanted, make sure this method make sense and better than the sole Edge detection algorithm,

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.363-369
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• 2015

This paper describes deployment of a sea based sensor platform for the detection of a submarine launched ballistic missile (SLBM). Recently, North Korea successfully conducted the underwater launching test of the SLBM, which will seriously threaten the global security. To defend these threats successfully, a sensor platform of the ballistic missile defense (BMD) should be deployed in the area of high detection probability of the missile. The maximum detection range characteristics of the typical radar sensor system, however, depend on the radar cross section (RCS) and flight trajectories of the target. In this point of view, this work analyzed the flight trajectories based on the tactics and calculated the RCS of the SLBM. In addition, sea based sensor platform position is proposed from the analysis of the detection time.