• Journal of Intelligence and Information Systems
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• v.18 no.1
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• pp.125-141
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• 2012

These days, the malicious attacks and hacks on the networked systems are dramatically increasing, and the patterns of them are changing rapidly. Consequently, it becomes more important to appropriately handle these malicious attacks and hacks, and there exist sufficient interests and demand in effective network security systems just like intrusion detection systems. Intrusion detection systems are the network security systems for detecting, identifying and responding to unauthorized or abnormal activities appropriately. Conventional intrusion detection systems have generally been designed using the experts' implicit knowledge on the network intrusions or the hackers' abnormal behaviors. However, they cannot handle new or unknown patterns of the network attacks, although they perform very well under the normal situation. As a result, recent studies on intrusion detection systems use artificial intelligence techniques, which can proactively respond to the unknown threats. For a long time, researchers have adopted and tested various kinds of artificial intelligence techniques such as artificial neural networks, decision trees, and support vector machines to detect intrusions on the network. However, most of them have just applied these techniques singularly, even though combining the techniques may lead to better detection. With this reason, we propose a new integrated model for intrusion detection. Our model is designed to combine prediction results of four different binary classification models-logistic regression (LOGIT), decision trees (DT), artificial neural networks (ANN), and support vector machines (SVM), which may be complementary to each other. As a tool for finding optimal combining weights, genetic algorithms (GA) are used. Our proposed model is designed to be built in two steps. At the first step, the optimal integration model whose prediction error (i.e. erroneous classification rate) is the least is generated. After that, in the second step, it explores the optimal classification threshold for determining intrusions, which minimizes the total misclassification cost. To calculate the total misclassification cost of intrusion detection system, we need to understand its asymmetric error cost scheme. Generally, there are two common forms of errors in intrusion detection. The first error type is the False-Positive Error (FPE). In the case of FPE, the wrong judgment on it may result in the unnecessary fixation. The second error type is the False-Negative Error (FNE) that mainly misjudges the malware of the program as normal. Compared to FPE, FNE is more fatal. Thus, total misclassification cost is more affected by FNE rather than FPE. To validate the practical applicability of our model, we applied it to the real-world dataset for network intrusion detection. The experimental dataset was collected from the IDS sensor of an official institution in Korea from January to June 2010. We collected 15,000 log data in total, and selected 10,000 samples from them by using random sampling method. Also, we compared the results from our model with the results from single techniques to confirm the superiority of the proposed model. LOGIT and DT was experimented using PASW Statistics v18.0, and ANN was experimented using Neuroshell R4.0. For SVM, LIBSVM v2.90-a freeware for training SVM classifier-was used. Empirical results showed that our proposed model based on GA outperformed all the other comparative models in detecting network intrusions from the accuracy perspective. They also showed that the proposed model outperformed all the other comparative models in the total misclassification cost perspective. Consequently, it is expected that our study may contribute to build cost-effective intelligent intrusion detection systems.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.637-645
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• 2013

Masan bay with a semi-enclosed waters has serious water quality problems due to the low flow and river pollution load from land, and shows the vulnerable locational characteristics to storm surge. We are seeking the way of both operating disaster prevention facilities and water quality improvement measures in the bay. That is, the water was exchanged using the head difference occurred by operating disaster prevention facilities. The location of disaster prevention facilities was assumed to be in the inlet of the bay, in the vicinity of Machang bridge, and in the vicinity of Dot island and the operation time was assumed to be early morning hours(01~05) considering the number of shipping passage and annual tide, and spring tide of the largest head difference. In addition, the experiment case of water exchange including the in-outflow feeder pipe was tested. According to the simulation results, water exchange rate in all experiments has shown a steady increase. Water exchange rate of the whole of Masan bay in the case of present is 38.62%. The water exchange rate of the inside of Masan bay compared with the inlet of bay, appeared to be very low. Thus, we judged that the characteristics of semi-enclosed waters were well reproduced. On the results of the experiment of disaster prevention facilities and in-outflow feeder pipe, the case of the operation of disaster prevention facilities, water exchage rate is high compared with the case of present. And, the higer the operating frequency, the more water exchange is appeared. The cases of water exchange prevention facilities through the in-outflow feeder pipe caused by the head difference, also showed the higest improvement of the water quality. Compared with the south of Machang bridge, the effect of water exchange was better in the inlet of Masan bay and Dot island. On the other hand, the inlet of Masan bay is higer than Dot island as for water exchange of the whole of Masan bay, but opposite, water change rate including Masan inside was higher in the case of Dot island.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.982-991
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• 2006

The screen quota system is one of the most controversial issues in the Korean film industry. There are two different points of view regarding the system. Some say it is highly effective to protect and nurture Korean movies. However, others argue that it hurts the duality of the Korean movies. The number of days, for which Korean movies have to play on local screens, has been reduced to 73, starting on July 1st, 2006. Actually, it is 50 percent fewer than the previous year. In facL Korea has implemented the screen quota. system two times. First, it was practiced from 1935 to 1945, during the Japanese colonial period. This was to regulate imported movies, especially American ones, as the Japanese government was to use movies for the political propaganda. In 1935, the number of foreign movies screened had to be less than three fourths of the total. And they gradually reduced the size by two thirds in 1936, and again by half in 1937. After the attack on Pearl Harbor when the Pacific War happened, Japan completely banned importing American movies in Korea. The reason why it regulated the imported foreign films is to increase the number of domestic movies, both Japanese and Korean. It was for making propaganda films fur carrying the war. The second practice of the screen quota is from 1967 to the present year. It was designed to boom the Korean film industry. However, the competitive power of Korean films has not been improved in spite of the practice of the system. Moreover, the film industry has gone through the depression. Korean film agencies have occupied the Korean film market thanks to the protection by government. The founding of the film agencies has been strongly regulated. So has importing foreign movies. Under the special protection like this, Korean film agencies have been enjoying the monopoly In the mean time, they have pursued income not by making quality movies but by importing foreign movies. As a result, cinema audiences turn away form Korean films and prefer foreign movies. Furthermore, the screen quota system hurts the relationship between film producers and distributors, imposing the duties only on theaters. In short, the screen quota system has satisfied neither film producers, theater runners, nor film goers. In other words. the excessive protection has weakened the competitive power of Korean film industry.

• The KIPS Transactions:PartA
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• v.13A no.2 s.99
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• pp.123-136
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• 2006

The prefetching technique is an effective way to reduce the latency caused memory access. However, excessively aggressive prefetch not only leads to cache pollution so as to cancel out the benefits of prefetch but also increase bus traffic leading to overall performance degradation. In this thesis, a prefetch filtering scheme is proposed which dynamically decides whether to commence prefetching by referring a filtering table to reduce the cache pollution due to unnecessary prefetches In this thesis, First, prefetch hashing table 1bitSC filtering scheme(PHT1bSC) has been shown to analyze the lock problem of the conventional scheme, this scheme such as conventional scheme used to be N:1 mapping, but it has the two state to 1bit value of each entries. A complete block address table filtering scheme(CBAT) has been introduced to be used as a reference for the comparative study. A prefetch block address lookup table scheme(PBALT) has been proposed as the main idea of this paper which exhibits the most exact filtering performance. This scheme has a length of the table the same as the PHT1bSC scheme, the contents of each entry have the fields the same as CBAT scheme recently, never referenced data block address has been 1:1 mapping a entry of the filter table. On commonly used prefetch schemes and general benchmarks and multimedia programs simulates change cache parameters. The PBALT scheme compared with no filtering has shown enhanced the greatest 22%, the cache miss ratio has been decreased by 7.9% by virtue of enhanced filtering accuracy compared with conventional PHT2bSC. The MADT of the proposed PBALT scheme has been decreased by 6.1% compared with conventional schemes to reduce the total execution time.

• Journal of radiological science and technology
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• v.28 no.2
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• pp.105-110
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• 2005

Background/Aim : Common bile duct (CBD) stones may cause jaundice, cholangitis, or pancreatitis. Extracorporeal shock wave lithotripsy (ESWL) may be needed whenever endoscopic procedure are failed to extract common bile duct stones. The aim of this study is to provide the standard for patient's best choice on ESWL for treatment of CBD stones resistant to endoscopic extraction. Materials and Methods : Fourty-six patients failed in endoscopic stone extraction including mechanical lithotripsy were treated by ESWL. In all patients, endoscopic sphincterotomy and nasobiliary drainage tube was done before ESWL using the ultrasonography for stone localization with a spark-gap type lithotriptor. Patients were sedated with an intravenous injection of 50 mg of Demerol. None were treated under general anesthesia. Results : Overall complete clearance rate of CBD stone was 89.1% (41/46). In 82.6% of the patients, the stones were extracted endoscopically after ESWL, and spontaneous passage was observed in 6.5%. In the clearance rate after ESWL, there were no noticeable differences with regard to number (single: 82.8%, two or three: 100%, more than three: 100%) and size of the stone (less than 33mm: 92.9%, 33 mm or larger: 83.3%), whereas there were significant differences with regard to the ratio of sum of long-axis length of the all stones to sum of long-axis length of the CBD excluding stone (1:2.4, 1:2.1) and diameter of the largest stone to diameter of CBD excluding stone (1:0.9, 1:0.4) for patients with complete clearance compared with those without. Conclusion : We propose that stones without the fragments are travelable sufficient space in CBD or extractable sufficient diameter of CBD regardless of stone size and number should be treated by other technique to prevent time and cost consuming, such as percutaneous transhepatic cholangioscopylithotomy.

• Journal of Korean Society of Rural Planning
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• v.20 no.4
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• pp.253-262
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• 2014

This, an association research for design-improvement and model-development of exhibition shops at rural tourism communities, is to secure objective data by analyzing customers' awareness-tendency of and demand for agricultural-specialty exhibition shops. Survey-questions for finding out consumers' awareness-tendency and demand were determined through brainstorming of a professional council, 30 rural communities of which visit-rate by consumers is considerably high were selected for the recruit of 200 consumers. For investigation and analysis, survey and in-depth interview were carried out at the scene with the application of frequency analysis and summarization of their opinions, which revealed that they have a strong will to visit the rural tourism communities for the purchase of agricultural specialties along with the experience of learning-program and on-the-scene direct dealing and that their viewpoint on the direct dealing at the scene was very positive. Also it was confirmed hat their satisfaction with the purchase of agricultural specialties by on-the-scene direct dealing, their pleasure at the purchase, their satisfaction with services and their intention for re-purchase of them were very high while their satisfaction with the exhibition shops was very low. With on-the-scene survey, the consumers' opinions could be listened to in depth. Almost all of them said their satisfaction with the trip to those rural tourism communities was considerably high since they could go to those communities themselves to relieve the stress from their modern life, to experience healing and to see the goods on the scene. Their satisfaction also was attributed to the fact that they have enough trust in purchase along with feeling the warm-heartedness of rural residents. As to their awareness of exhibition shops, they showed a positive response to the on-the-scene direct dealing at rural communities while they, thinking that the space in those exhibition shops was not sufficiently wide, demanded for more systematic counters in more accessible and affordable exhibition shops so that they might be more satisfied with the exhibition shops. Their demand for the necessity of exhibition shops selling agricultural specialties was found to be over 80%, which indicates that the necessity is very high. As to the suitability of function, they have the opinion that the business at those shops had better be focused on sales since they have the understanding of information when they take a trip to the rural communities, while there was another opinion: since agricultural products are seasonal items they should be exhibited and sold at the same time. More than 90% of the respondents had a positive viewpoint on direct dealing of agricultural specialties on the scene, which showed that their response to it was very high. They preferred the permanent shops equipped with roll-around table-booths. In addition, it was revealed that they want systematic exhibition shops in rural communities because they frequent those communities for on-the-scene direct purchase. The preferred type and opinion resulting from estimation of consumers' demands have been reflected for development of practical designs. The structure of variable principles has been designed so that the types of display-case and table-booth might be created. The result of this study is a positive data as a design model which can be utilized at rural communities and will be commercialized for the verification of its validity.

• Journal of radiological science and technology
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• v.27 no.2
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• pp.29-33
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• 2004

Until early 1980s we have lived without thinking that radon ruins our health. But, scientists knew truth that radon radioactive danger is bedeviling on indoor that we live for a long time. Specially, interest about effect that get in danger and injury for Radon and human body is inactive in our country. Recently, with awareness for Radon contamination, We inform about importance and danger of Radon in some station of the Seoul subway, indoor air of school facilities and We had interest with measure and manages. Usually, Radon gas emitted in base of building enters into indoor through building floor split windage back among radon or indoor air of radon daughter nucleus contamination is increased. Therefore, indoor radon concentration rises as there are a lot of windages between number pipe of top and bottom and base that enter crack from estrangement of the done building floor, underground to indoor. Thus, Radon enters into indoor through architecture resources water as well as, kitchen natural gas for choice etc., but more than about 85% from earth's crust emit. Danger and injury of health by Radon and Radon daughter nucleus that is indicated for cause of lung cancer incerases content of uranium of soil rises specially from inside pit of High area and a mine, cave, hermetical space with house. Safe sub-officer of radon concentration can not know and danger always exists large or small during. So, Important thing reduces danger of lung cancer by lowering concentration of Radon within house and building. Therefore, is thought that need general house Radon concentration measurement, measured Radon concentration monthly using Sintillator radon monitor. Study finding appeared high all underground market 1 year than the ground, and the winter appeared high than the summer. Specially, month that pass over 4pCi in house that United States Environmental Protection Agency advises appeared in underground, and appeared and know Radon exposure gravity by 4 months during 12 months. Therefore, Thinking that establishment and regulation of norm and preparation of reduction countermeasure about Radon are pressing feels, and inform result that measure Radon concentration.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.567-573
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• 2017

The purpose of this study was to evaluate whether or not there was artifact when the upper limb could not be lifted to the top of the head during multi-detector computed tomography(MDCT) scans of the chest and abdomen. Contrast radiography of the human and chest phantom was performed with 128channal MDCT. Under the same conditions(120 kVp, 110 mAs, standard algorithm)both hands lifted up and put down each time in the human experiment. In the chest phantom experiment, the radiography was carried out when the upper limb phantom was adjusted at a certain distance(0, 3, 7 cm) from the chest phantom. Subsequently, the values of Noise, CT number, SNR, and CNR were measured in the field of concern. The noise value of fat, rib, and muscle increased when the arm was lifted in humans(0.79, 47.8, 27%). Furthermore, when the upper limb was lowered, the noise value of muscle and lung increased in the phantom(31.2, 9.4%). In addition, the noise value of the muscles and lung decreased by 5, 25.12% and 5.6, 15.35% as the upper limb moved about 0,3,7cm away from the chest. When the chest and abdominal radiography were performed, in the case of the presence of other parts outside the inspection area, the probability of artifact was minimal while the distance was more than 3cm away from the upper limb to the chest and abdomen.

• Korean Journal of Remote Sensing
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• v.31 no.6
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• pp.531-548
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• 2015

Atmospheric Motion Vector (AMV) from satellite images have shown Slow Speed Bias (SSB) in comparison with rawinsonde. The causes of SSB are originated from tracking, selection, and height assignment error, which is known to be the leading error. However, recent works have shown that height assignment error cannot be fully explained the cause of SSB. This paper attempts a new approach to examine the possibility of SSB reduction of COMS AMV by using a new target tracking algorithm. Tracking error can be caused by averaging of various wind patterns within a target and changing of cloud shape in searching process over time. To overcome this problem, Gaussian Mixture Model (GMM) has been adopted to extract the coldest cluster as target since the shape of such target is less subject to transformation. Then, an image filtering scheme is applied to weigh more on the selected coldest pixels than the other, which makes it easy to track the target. When AMV derived from our algorithm with sum of squared distance method and current COMS are compared with rawindsonde, our products show noticeable improvement over COMS products in mean wind speed by an increase of $2.7ms^{-1}$ and SSB reduction by 29%. However, the statistics regarding the bias show negative impact for mid/low level with our algorithm, and the number of vectors are reduced by 40% relative to COMS. Therefore, further study is required to improve accuracy for mid/low level winds and increase the number of AMV vectors.

• Korean Journal of Remote Sensing
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• v.31 no.6
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• pp.501-512
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• 2015

Landfast sea ice (LFI) in Terra Nova Bay, East Antarctica where the Jangbogo Antarctic Research Station is located, has significant influences on marine ecosystem and the sailing of an icebreaker. Therefore, it is essential to analyze the spatio-temporal variation of the LFI in Terra Nova Bay. In this study, we chose interferometric pairs with the temporal baseline from 1 to 9 days out of a total of 62 COSMO-SkyMed synthetic aperture radar (SAR) images over Terra Nova Bay obtained from December 2010 to January 2012, and then constructed the coherence image of each pair. The LFI showed coherence values higher than 0.3 even in the interferometric SAR (InSAR) pairs of up to 9-days of temporal baseline. This was because the LFI was fixed at coastline and thus showed low temporal phase decorrelation. Based on the characteristics of the coherence on LFI, We defined the areas of LFI that show spatially homogeneous coherence values higher than 0.5. Pack ice (PI) and open water showed low coherence values due to large temporal phase decorreation caused by current and wind. Distinguishing PI from open water in the coherence images was difficult due to their similarly low coherence values. PI was identified in SAR amplitude images by investigating cracks on the ice. The extents of the LFI and PI were estimated from the coherence and SAR amplitude images and their temporal variations were analyzed. The extent of the LFI increased from March to July (maximum extent of $170.7km^2$) and decreased from October. The extent of the PI increased from February to May and decreased from May to July when the LFI increases dramatically. The extent of the LFI and air temperature showed an inverse correlation with a time lag of about 2 months, i.e., the extent of the LFI decreases after 2 months of the increase in the air temperature. Meanwhile the correlation between wind speed and the extent of the LFI was very low. This represents that the extent of LFI in Terra Nova Bay are influenced more by the air temperature than wind speed.