• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.3
• /
• pp.75-81
• /
• 2014

In a distribution of the digital image, there is a serious problem that is distributed an illegal forgery image by pirates. For the problem solution, this paper proposes an image forensic decision algorithm using an edge energy information of forgery image. The algorithm uses SA (Streaking Artifacts) and SPAM (Subtractive Pixel Adjacency Matrix) to extract the edge energy informations of original image according to JPEG compression rate(QF=90, 70, 50 and 30) and the query image. And then it decides the forge whether or not by comparing the edge informations between the original and query image each other. According to each threshold in TCJCR (Threshold by Combination of JPEG Compression Ratios), the matching of the edge informations of original and query image is excused. Through the matching experiments, TP (True Positive) and FN (False Negative) is 87.2% and 13.8% respectively. Thus, the minimum average decision error is 0.1349. Also, it is confirmed that the performed class evaluation of the proposed algorithm is 'Excellent(A)' because of the AUROC (Area Under Receiver Operating Characteristic) curve is 0.9388 by sensitivity and 1-specificity.

• 한국해양학회지
• /
• v.18 no.2
• /
• pp.125-141
• /
• 1983

Micropaleontological analyses of the bathic foraminifera of 132 subtidal surface samples of Asan Bay located in the middle of the western coast of Korea, fringing the Yellow Sea collected during late May-early June 1982, shows the results as follows; -Forainiferal numbers of total assemblages are influenced by hydrodynamic and ecologic factors as well as by the sedimentation in the study area. -Badly preserved faunas including replaced faunas seemed to be fossils, all having living counterparts in the study area and showing a somewhat similar type of wall structures with those of the total assemblages and showing no characteristic bathymetric occurrence compared to that of the biocoenose s.1. of the species, lead to infer theirprobable derivation from the environment without a remarkable environmental difference from the study area. But this inference demands further study in consideration of the physical conditions of the study area. -Living/total ratios show a strong negative correlation with the total foraminiferal numbers excluding replaced faunas. But this trend is somewhat deviated in the relatively high ratios. -Fisher-alpha diversity indices of the total assemblages excluding replaced faunas are lying between 1.7 and 3.7. Totals assemblages are mainly composed of hyaline forms with limited porcelaneous and agglutinated ones.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.2
• /
• pp.159-165
• /
• 2007

The Characteristics of the flowfield around two circular cylinders in tandem arrangement was investigated by PIV. Strouhal numbers. velocity vectors and velocity profiles were observed at centre-to-centre space ratios of P/D= 1.5. 2.0 and 2.5, and Reynolds number of $Re=3.0{\times}10^3{\sim}5.0{\times}10^3$. As the results the Strouhal numbers measured in the rear region of the cylinder of wake side were decreased with the space ratios. The flow between two cylinders was almost stagnated and the size of the stagnated region was larger in the close side than in the far side of the front cylinder. The direction of vortex between two cylinders was opposed each other with the small difference(${\alpha}\;{\pm}1.0^{\circ}$) of the attack angle ${\alpha}$.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.961-965
• /
• 1992

It is well-known that shock waves frequently occur inside the nozzle of the interrupter, and that they play important roles in the arc interruption. A model interrupter with two-dimensional dual-airflow nozzles was used for this experiment. The arc was ignited with 1.4 mil copper wire stretched between the electrodes which were spaced out 56 mm. The arc current of 60 to 230 A was achieved by adjusting the external resistance from 5.5 to 1.6 ohms. The arc tests have been conducted for investigating the air arc characteristics, and the effects of shock waves and nozzle pressure ratios on the arc voltage, the arc resistance, the arc power, and average electric field. The results of these tests have been analyzed to provide insights into the arc characteristics for gas circuit breakers. The average electric field is represented by the function of the arc current to show the negative E-I characteristic explicitly. The effects of shock waves and nozzle pressure ratios are shown to be significant for a circuit breaker performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.2
• /
• pp.131-136
• /
• 2008

The characteristics of the flowfields around two circular cylinders in various arrangements were investigated by PIV. In tandem arrangement, the Strouhal numbers measured in the rear region of the cylinder of wake side were decreased with the space ratios, the flow between two cylinders was almost stagnated and the closer to upstream cylinder, the larger the width of the stagnated region was. The direction of vortex between two cylinders was opposed each other with the small difference(${\alpha}$=${\pm}1.0^{\circ}$) of the attack angle . In side by side arrangement, the flow velocity between two circular cylinders were increased with the space ratios.

• Computers and Concrete
• /
• v.25 no.5
• /
• pp.411-425
• /
• 2020

In this paper, the shell material has been taken as functionally graded material and their material quantity is located by the exponential volume fraction law. Moreover, the impact of ring supports around the shell circumference has been examined for their various positions along the shell axial length. These rings support restraints the radial displacement in the transverse direction. While the axial modal deformation functions have been estimated by characteristic beam functions and nature of materials used for construction of cylindrical shells. The fundamental natural frequency of cylindrical shell of parameter versus ratios of length- and height-to-radius for a wide range has been reported and investigated through the study. In addition, by increasing height-to-radius ratio resulting frequencies also increase and frequencies decrease on ratio of length-to-radius. Though the trends of frequency values of both ratios are converse to each other with three different boundary conditions. Also it is examined the position of ring supports with length-to radius ratio, height-to-radius ratio and varying the exponent of volume fraction. MATLAB software package has been utilized for extracting shell frequency spectra. The obtained results are confirmed by comparing with available literature.

• 유체기계공업학회:학술대회논문집
• /
• 2005.12a
• /
• pp.302-307
• /
• 2005

The discharge coefficient in segmental wedge having ninety degrees vertex angle for the five kinds of opening ratio with differential pressure taps located at both upstream and downstream of one diameter of pipe was measured main purpose of this work is placed on developing the proper form of an equation for the discharge coefficient of a segmental wedge used as a primary element of flow metering devices, and from thata six-term equation which can express the variability of opening ratios was developed. The same assumption and hypotheses were used and tested for all procedures as conventional differential producers; however, the range of the opening ratio over this work is more expanded than previous studies. The opening ratios of segmental wedge, namely 0.3, 0.4, 0.5, 0.6 and 0.7 were investigated the Reynolds number based on the spool inside diameter ranges from 12,000 to 380,000, the resulting equation for the discharge coefficient is relatively simple; it contains only one variable-opening ratio because the characteristic of discharge coefficient of segmental wedge has little connection with the Reynolds number as shown by previous studies.

• The Korean Journal of Nuclear Medicine
• /
• v.15 no.1
• /
• pp.13-20
• /
• 1981

Using stannous chloride, optimum conditions for $^{99m}Tc$ labelling of some scanning agents such as phytic acid (P A), dimercaptosuccinic acid (DMSA), and calcium diethylenetriaminepentaacetate (Ca-DPTA) were established. Methods of separation and identification of the labelled compounds were practiced by a paper- or thin layer- chromatography. Biodynamic studies of the compounds were also carried out. The results indicate that the molar ratios of the chelating agent and stannous chloride varies only with the concentrations of the chelating agents, and thus the amounts of the stannous chloride per labelling tube were nearly constant $(500\sim600{\mu}g)$ regardless the variation of the molar ratios. It suggests that the given experimental conditions require about $500{\mu}g$ of stannous chloride regardless of the chelating agents. Under alkaline pH, the labelling yields were drastically decreased due to the probable formation of colloidal tin compounds. Biodynamic data showed characteristic patterns with each compound indicating that they are all suitable for the relevant scanning applications.

• Journal of Animal Science and Technology
• /
• v.62 no.1
• /
• pp.74-83
• /
• 2020

Organic waste used as a feedstock in the anaerobic digestion (AD), it includes carbon and nitrogen. Carbon and nitrogen have an effect on the various digestive characteristics during AD, however, the study is rare about those of the interaction. This study investigates the influence of carbon type and carbon to nitrogens (C/N ratios) on the AD characteristics of organic waste. Experimental treatments involved a combination of three carbon types with three C/N ratios. The AD tests were carried out using a 125-mL serum bottle at a constant temperature of 37℃ and moisture 95% for 18 days. Degradation pattern shows the difference among three-carbon treatments, the starch group was faster than other groups. Maximum methane production date was similar between starch (9.96 ± 0.05 day) and xylan group (10.0 ± 0.52 day), those of the cellulose group (14.6 ± 1.80 day) was slower than other groups (p < 0.05). The lag phase was only affected by the carbon type (p < 0.05). Ammonia nitrogen was mainly affected by nitrogen concentration regardless of carbon type (p < 0.05). This study showed that xylan is useful as feedstock in order to decrease the lag phase, and it showed that ammonia was independently affected by the nitrogen concentration.

• Imaging Science in Dentistry
• /
• v.34 no.3
• /
• pp.117-122
• /
• 2004

Purpose : To determine the proper image compression method and ratio without image quality degradation in intraoral digital radiographic images, comparing the discrete cosine transform (DCT)-based JPEG with the wavelet-based JPEG 2000 algorithm. Materials and Methods : Thirty extracted sound teeth and thirty extracted teeth with occlusal caries were used for this study. Twenty plaster blocks were made with three teeth each. They were radiographically exposed using CDR sensors (Schick Inc., Long Island, USA). Digital images were compressed to JPEG format, using Adobe Photoshop v.7.0 and JPEG 2000 format using Jasper program with compression ratios of 5 : 1,9 : 1, 14 : 1,28 : 1 each. To evaluate the lesion detectability, receiver operating characteristic (ROC) analysis was performed by the three oral and maxillofacial radiologists. To evaluate the image quality, all the compressed images were assessed subjectively using 5 grades, in comparison to the original uncompressed images. Results: Compressed images up to compression ratio of 14 : 1 in JPEG and 28 : 1 in JPEG 2000 showed nearly the same the lesion detectability as the original images. In the subjective assessment of image quality, images up to compression ratio of 9 : 1 in JPEG and 14 : 1 in JPEG 2000 showed minute mean paired differences from the original Images. Conclusion : The results showed that the clinically acceptable compression ratios were up to 9 : 1 for JPEG and 14 : 1 for JPEG 2000. The wavelet-based JPEG 2000 is a better compression method, comparing to DCT-based JPEG for intraoral digital radiographic images.