• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1721-1736
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• 2013

Black and gray hole attack is one kind of routing disturbing attacks and can bring great damage to the network. As a result, an efficient algorithm to detect black and gray attack is important. This paper demonstrate an adaptive approach to detecting black and gray hole attacks in ad hoc network based on a cross layer design. In network layer, we proposed a path-based method to overhear the next hop's action. This scheme does not send out extra control packets and saves the system resources of the detecting node. In MAC layer, a collision rate reporting system is established to estimate dynamic detecting threshold so as to lower the false positive rate under high network overload. We choose DSR protocol to test our algorithm and ns-2 as our simulation tool. Our experiment result verifies our theory: the average detection rate is above 90% and the false positive rate is below 10%. Moreover, the adaptive threshold strategy contributes to decrease the false positive rate.

• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1869-1875
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• 2001

The paper presents computational and flow visualization results on a centrifugal blood pump. 4 impeller designs were tested at a rotational speed of 2000 rpm using blood analog as working fluid. All impellers have seven blades but of different geometry (Impellers A3, A4, B2 and R7). Flow visualization within the impeller passages was conducted using an image de-rotation system. A pair of large scale vortices was found within the blades of impeller R7 while a single vortex was found in most of the passages of backward facing impellers (Impellers A3, A4 and B2). To establish the effects of blade geometry on blood cells, CFD was used to simulate the blade to blade flow to provide an estimate of the maximum shear stress. The results showed that though most of the stresses within the blade passages are below a threshold level of 150 N/m$^2$for extensive erythrocyte damage to occur, there are some regions near to the leading edge of the pressure side where the shear stresses a abode threshold level.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.1-6
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• 2009

The experimental results of exposing IGBT (Insulated Gate Bipolar Transistor) samples to gamma radiation source show shifting of threshold voltages in the MOSFET and degradation of carrier mobility and current gains. At low total dose rate, the shift of threshold voltage is the major contribution of current increases, but for more than some total dose, the current is increased because of the current gain degradation occurred in the vertical PNP at the output of the IGBTs. In the paper, the collector current characteristics as a function of gate emitter voltage (VGE) curves are tested and analyzed with the model considering the radiation damage on the devices for gate bias and different dose. In addition, the model parameters between simulations and experiments are found and studied.

• Journal of the Semiconductor & Display Technology
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• v.11 no.1
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• pp.79-83
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• 2012

We use adaptive method and determine threshold coefficient so that the algorithm could decide a suitable binarization threshold coefficient of the image to detecting a marker; therefore, we solve the light influence on the shadow area and dark region. In order to improve the speed for reducing computation we created Integral Image. The algorithm detects an outline of the image by using canny edge detection for getting damage or obscured markers as it receives the noise removed picture. The strength of the line of the outline is extracted by Hough transform and it extracts the candidate regions corresponding to the coordinates of the corners. Markers extracted using the equation of a straight edge to find the coordinates. By using the equation of straight the algorithm finds the coordinates the corners. of extracted markers. As a result, even if all corners are obscured, the algorithm can find all of them and this was proved through the experiment.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.161-170
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• 2014

Analog cassette tapes are easily changed due to environmental factors. To digitize is the best way to preserve a sound source. The way to digitize is to deal with the original sound to be enhanced to a variety of sources by playing through the audio card after recording. In this process to occur, it's the most important to remove various noise and equalizing sound in a method for preserving. It's studied about how to remove noise by using one of softwares, Cubase 5. 5, to remove hiss noise, which happens changing analog tape into digitalization. A amount of hiss noise is reduced to use X-Noise software of Wave which uses in Cubase 5.0, one of PLUG-IN. The noise is removed changing value of threshold and reduction every 10 times in no change of origin sound. To keep regular condition, the experiment to remove the hiss noise is conducted based on sound meondle, which is one of sound Nonmaegi. The noise is removed easily when the value of threshold is getting high in spite of giving a little value of reduction. However, as it gives a amount of reduction high, the damage rate of the sound source gets high.

• Journal of the Korean Data and Information Science Society
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• v.20 no.5
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• pp.797-807
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• 2009

In a case of an automobile rear-end collision, scale of the collision which are the extent of vehicle damage and the injury of the passenger is affected by the speed change. Based on the photographic interpretation of the actual accident cases in the Seoul and the Incheon area, this study measured the depth of crush and calculated the speed change from the statement data of the accident and speed, and also injury data such as diagnosis, hospitalization days are collected. The period of hospitalization and diagnostics claimed proves to have no statistical correlation with the depth of vehicle crush and speed change. Based on the statistical analysis from this study and previous foreign studies, we found that there have been 78.1% of personal accidents didn't reach the injury threshold. There should be objective information on the scale of accident accepting the claims-to-be-injured in the future, and application of injury threshold level suggested are considered to be very useful.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.661-663
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• 2016

Corruption occurs in the process of processing image signal and the corruption changes the pixel value within the image to damage the original information. AWGN(additive white Gaussian noise) is a representative example. For filters to remove AWGN, there are filters such as MF(mean filter), WF(wiener filter), and AWMF(adaptive weighted mean filter). However images processed through standard previous filters lock preservation characteristics in edge areas. Therefore, threshold value is applied for processing on the standard deviation of the local mask in this study and if the standard deviation is smaller than the threshold value, it is not filtered and if the value is bigger than the threshold value, the study suggested an algorithm that processes using weighted value utilizing standard deviation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2509-2515
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• 2014

In this paper, the conventional vertical structure for VLSI circuits CMOS intend to improve the stress effects of active region and built-in threshold voltage. For these improvement, the proposed structure is shallow trench isolation of moat shape. We want to analysis the electron concentration distribution, gate bias vs energy band, thermal stress and dielectric enhanced field of thermal damage between vertical structure and proposed moat shape. Physically based models are the ambient and stress bias conditions of TCAD tool. As an analysis results, shallow trench structure were intended to be electric functions of passive as device dimensions shrink, the electrical characteristics influence of proposed STI structures on the transistor applications become stronger the potential difference electric field and saturation threshold voltage, are decreased the stress effects of active region. The fabricated device of based on analysis results data were the almost same characteristics of simulation results data.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.147-155
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• 2023

Purpose: Headache is a very common disease experienced at least once in daily life, and tension-type headaches have a high and increasing prevalence. Chronic headaches can cause functional damage and huge socioeconomic impacts. This study aimed to compare the effects of myofascial release technique with manual therapy and self-myofascial release technique using a foam roller on the pain threshold and body schema in patients with chronic tension-type headaches. Methods: The study was conducted on 20 patients living in Busan with chronic tension headaches. Myofascial release technique with manual therapy was performed on the suboccipital, sternocleidomastoid, scalene, and upper trapezius muscles. The self -myofascial release technique using a foam roller was applied to the cervical and thoracic muscles. A laterality test was performed using a recognized neck application developed to evaluate body schema ability. A pressure-pain threshold test was performed using an electronic pressure algometer to compare the results before and after the myofascial release technique. Results: After applying myofascial release with manual therapy and a foam roller, the pressure-pain threshold values showed significant changes in both groups (p<.05). As a result of the laterality test, myofascial release with manual therapy and a foam roller were applied to the painful area. The values showed significant changes in both groups (p<.05), but only the group using the foam roller showed a significant difference (p<.05) in painless areas. Conclusion: The myofascial release technique with manual therapy can be the primary treatment technique for pain control in painful areas. The self-muscle release technique using a foam roller can be an effective method when there is no pain or when maintenance is needed after pain control.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.498-504
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• 1994

The damage by the black-tipped sawfly, Acantholyda posticalis posticalis Matsumura, has been incheasing at several locations in central part of the Korean peninsula. This study was undertaken at selected plots in locality of Kapyung-gun. Kyunggi Province from 1984 through 1987. The purpose of this study was to provide basic information for integrated control of this pest and to determine the economic threshold by investigating the pest-host interactions with special reference to damage analysis. The results obtained were as follows ; 1. One year old cone formation began to be reduced when 30-40% of the needles were destroyed. With 70% of defoliation, few cones were produced. 2. Number of two year old cone formation and amount of cones began to be reduced when 61-70% of the needles were destroyed ; economic threshold of the defoliation rate retarding the seed production was 51%. 3. Growth of the trees was significantly reduced when more than 50% of the needles were destroyed, and cone production began to be retarded at 30-40% of defoliation. Therefore, it was determined that the economic thresholds requiring the control practices to keep normal tree growth and cone production from being reduced were 50% and 30%, respectively.