• ETRI Journal
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• v.36 no.3
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• pp.479-489
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• 2014

This paper presents a model-based image steganography method based on Watson's visual model. Model-based steganography assumes a model for cover image statistics. This approach, however, has some weaknesses, including perceptual detectability. We propose to use Watson's visual model to improve perceptual undetectability of model-based steganography. The proposed method prevents visually perceptible changes during embedding. First, the maximum acceptable change in each discrete cosine transform coefficient is extracted based on Watson's visual model. Then, a model is fitted to a low-precision histogram of such coefficients and the message bits are encoded to this model. Finally, the encoded message bits are embedded in those coefficients whose maximum possible changes are visually imperceptible. Experimental results show that changes resulting from the proposed method are perceptually undetectable, whereas model-based steganography retains perceptually detectable changes. This perceptual undetectability is achieved while the perceptual quality - based on the structural similarity measure - and the security - based on two steganalysis methods - do not show any significant changes.

• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.154-160
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• 1997

Present experiment designed for the review of theoretical basis for the inspection system of infected insects by Nosema bombycis. A microporidian N. bombycis, known as the high virulence, produced at the average of 7$\times$108 spores per female moth of the silkworm, Bombyx mori, enabled transovarial tranmission. Detectability of N. bombycis spores in the mass inspection was varied by dillution level, the higher limit of dillution with healthy moths was 1:140 for 100% detection, 1:160 for 99.5%, 1:200 for 99.0%. For an efficient inspection under the microscopic observation (600$\times$), the lower limit of spore concentration was determined as 1, 000, 000 spores/ml, 60-80 moths could be applicable for a maximum sample unit of a lot. Following the present inspection unit conditioned 35 to 40 moths for a lot. N. bombycis spores were easily detectable from the preparation of crude homogenate with 2% KOH, even the step of contrifuge was omitted. The results suggested a new basis of rational mass inspection system of silkworm female moths to save the facilities, labor, and time.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.194-203
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• 1982

In this investigation we undertook to evaluate the utility of radionuclide cardiac angiography in the detection of cardiac shunts before and after surgical correction. Time-activity curves of ventricles and lungs were evaluated after bolus intravenous injection of 99mTc-human serum albumin in 512 preoperative patients and 551 post-operative patients. Omitting 31 cases of technical failure due to poor bolus, we detected shunts in 459 cases of 481 preoperative evaluations, so the detectability was 95.4%. The cases which couldn`t be detected by this method had small amount of shunt. Also the degree of shunt detected by radioisotope methods were well correlated with oxymetry method. [r=0.89, p<0.01 ] In postoperative evaluations, 18 out of 411 patients with left to right shunt and 10 out of 140 right to left shunt were found to have remnant shunts with radionuclide cardiac angiography. Of the 28 cases with failed operation, 2 were confirmed in reoperation, 2 by cardiac catheterization, 2 by two -dimensional echocardiography. All except one .f these patients had membranous ventricular septal defects and those with left to right shunts had moderate to severe pulmonary hypertension and shunt amount. Also those had larger septal defects than control group. We consider that radionuclide cardiac angiography is a simple and noninvasive method which can show the preoperative diagnosis and postoperative follow up of cardiac shunts.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.124-130
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• 2009

This study presents a finite element simulation of elastic waves for detecting anti-symmetric damages in an adhesively-bonded single lap joint. Plane strain elements were used for modeling adherents (aluminum) and adhesives (epoxy). Three types of damage were introduced: thickness reduction, elasticity deterioration, and voids in the adhesive layers, and two excitation and reception arrangements (ER1 and ER2) were used to investigate the detectability of the damage. The simulation showed that symmetrically located damage, such as a thickness reduction, can be detected by one excitation and one reception arrangement (ER1) and anti-symmetric damages, such as elasticity deterioration and voids, can be detected by modified two-point elastic wave excitation (ER2). Compared with the ER1 arrangement, the ER2 arrangement does not require a baseline signal for damage detection; hence, an efficient method of anti-symmetric damage detection in an adhesively-bonded single lap joint is proposed.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.36-41
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• 2004

This paper presents an qualitative assessment for hazard on the electric power installations of a construction field using FMEL The power installations have the mission to maintain the highest level of service reliability on the works. The more capital the electric power invest the higher service reliability they plausibly will achieve. However, because of limited resources, how effectively budgets can be allocated to achieve service reliability as high as possible. The assessment typically generates recommendations for increasing component reliability, thus improving the power installation safety. The FMEA tabulates the failure modes of components and how their failure affects the power installations being considered. Tn order to estimate the risks of a failures, the FMEA presents criticality estimation or risk priority number using the severity, occurrence, and detectability. The results showed that the highest components of the risk priority number among components were condenser, transformer, MCCB and LA. And In case of the criticality estimation, the potential failure modes were abnormal temperature rise, insulation oil leakage, deterioration for the transformer, overcurrent for the MCCB and operation outage fir the LA.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.4
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• pp.502-512
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• 2013

Simulations of cavitation flow and hull pressure fluctuation for a marine propeller operating behind a hull using the unsteady Reynolds-Averaged Navier-Stokes equations (RANS) are presented. A full hull body submerged under the free surface is modeled in the computational domain to simulate directly the wake field of the ship at the propeller plane. Simulations are performed in design and ballast draught conditions to study the effect of cavitation number. And two propellers with slightly different geometry are simulated to validate the detectability of the numerical simulation. All simulations are performed using a commercial CFD software FLUENT. Cavitation patterns of the simulations show good agreement with the experimental results carried out in Samsung CAvitation Tunnel (SCAT). The simulation results for the hull pressure fluctuation induced by a propeller are also compared with the experimental results showing good agreement in the tendency and amplitude, especially, for the first blade frequency.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.10
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• pp.1039-1046
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• 2009

In this work, a bilateral control for a master-slave manipulator system which will be used for handling objects contaminated by radioactivity has been addressed. The links of manipulators are driven independently by individual motors installed on the base and the driving torque is transmitted through pre-tensioned tendons. The measurable variables are the positions and rates of master/slave motors. In the consideration of the flexibility of the tendon and available measurements for control, we proposed an optimal static output feedback control for possible bilateral control architecture. By using modal analysis, the system model is reduced to guarantee the detectability which is a necessity for the static output feedback control design. Based on the reduced model, the control gains are determined to attenuate vibration in the sense of optimality. The feasibility of the proposed control design was verified along with some simulation results.

• The Journal of Korean Academic Society of Nursing Education
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• v.19 no.4
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• pp.675-683
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• 2013

Purpose: Nineteen articles were analyzed to gather opinions and nursing implications about NIPT recently launched. Methods: Nineteen articles were selected from EBSCO (eBook business collection), Google Scholar, and two Korean academic d-bases with key words 'prenatal screening testing', 'prenatal genetic diagnostic testing', NIPT or 'cell free DNA (cfDNA)'. Authors developed a framework for analyzing the 19 articles including opinions and suggestions for future implications. Results: Eleven articles written by the first author affiliated with medicine or genetics, viewed NIPT as promising because of safety, accuracy, early detectability and cost effectiveness. Articles written by journalists or authors affiliated with history and ethics were concerned with the possible risk of ELSI (ethical, legal, social issues), erratic interpretation of test results, and lack of genetic counseling service. Conclusion: With consideration of Korean clinical, and legal circumstances, not only pregnant women and families but also health professionals must prepare for clinical NIPT implications including updating prenatal genetic testing, counseling services, protecting ELSI and amulticultural team approach.

• Journal of IKEEE
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• v.24 no.2
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• pp.502-506
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• 2020

With the development of autonomous driving technology, the importance of object recognition technology is increasing. Haze removal is required because the hazy weather reduces visibility and detectability in object recognition. However, the image from which the haze has been removed cannot properly reflect the unique color, and a detection error occurs. In this paper, we use CIE1931 color coordinate system to extend or reduce the color area to provide algorithms and hardware that reflect the colors of the real world. In addition, we will implement hardware capable of real-time processing in a 4K environment as the image media develops. This hardware was written in Verilog and implemented on the SoC verification board.

• Economic and Environmental Geology
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• v.20 no.1
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• pp.77-82
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• 1987

An analysis is made for the relative effectiveness in detecting a subsurface thin layer by four electromagnetic depth sounding systems; horizontal coplanar loops, perpendicular loops, vertical coplanar loops and vertical coaxial loops. The moduli and phases of mutual coupling ratios over a three-layered earth for the four systems are evaluated rapidly by the related convolution technique. Root mean square differences between the responses from the three-layered and the homogeneous earths are used to compare the relative effectiveness of the systems quantitatively. Comparing the all systems, it is found that the perpendicular loop system appears to be the most superior to the other systems.