• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.1
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• pp.29-40
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• 2005

In this paper we consider the security of recently proposed software-orienred stram cipher HELIX, SCREAM, MUGI, and PANAMA against algebraic attacks. Algebraic attack is a key recovery attack by solving an over-defined system of multi-variate equations with input-output pairs of an algorithm. The attack was firstly applied to block ciphers with some algebraic properties and then it has been mon usefully applied to stream ciphers. However it is difficult to obtain over-defined algebraic equations for a given cryptosystem in general. Here we analyze recently proposed software-oriented stream ciphers by constructing a system of equations for each cipher. furthermore we propose three design considerations of software-oriented stream ciphers.

• Journal of Mushroom
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• v.15 no.3
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• pp.129-133
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• 2017

Oyster mushroom is a type of mushroom that is commonly cultivated and consumed in Korea. P. ostreatus 'Suhan' is a preferred cultivar for many mushroom farmers because it has a dark pileus and thick stipe. However, as it is very sensitive to environmental conditions, farmers consistently demand an alternative cultivar. To develop a new cultivar, the parental strains KMCC01680 ('Suhan') and KMCC00478 ('Gosol') were selected from various collected P. ostreatus strains by cultivating genetic resources. P. ostreatus 'Heuksol' was developed by the method of Mon-Mon crossing between monokaryotic strains derived from 'Suhan' and 'Gosol'. Thirty strains of 174 crossed strains were initially selected by cultivation experiments. After bulk cultivation tests, 'Heuksol' was selected. The nuclear DNA profile of 'Heuksol' was similar to those of the parental strains, 'Suhan' and 'Gosol', when RAPD (random amplified polymorphic DNA) primers and UPF (Universal PCR Fingerprinting) 2, 3, and 4 were used. The optimum temperature for mycelial growth was $30^{\circ}C$ for 'Heuksol', but medium-high temperatures were also appropriate, especially $13-20^{\circ}C$. The fruiting body production per bottle (1,100 mL) was approximately 140.8 g. When compared to the control strain 'Suhan', the thickness of the stipe of 'Heuksol' was greater than that of 'Suhan' (13.5 mm vs 9.4 mm). The pileus diameter of 'Heuksol' was similar to that of 'Suhan' and the pileus thickness of 'Heuksol' and 'Suhan' was 19.7 mm and 21.8 mm, respectively. 'Heuksol' had more a productive stipe number than 'Suhan' and the pileus of 'Heuksol' was dark gray, even at high temperatures. Therefore, it was suggested that this new cultivar, 'Heuksol', could provide an alternative to 'Suhan' and contribute to the profit of oyster mushroom farms.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.105-114
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• 2008

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Separated sewer overflows(SSO) have been considered as a major cause of water-quality deterioration of natural water-courses in the vicinity of the heavily urbanized areas. The factors defining the magnitude and occurrence of SSO are site-specific. It is important to know exact properties of pollutants contained in SSO to address water quality impacts that are caused by SSO inputs to the receiving waters. Site and event parameters found to have significant influences on urban runoff pollutant EMCs include total event rainfall, antecedent dry period, rainfall intensity. In this study, a field survey was carried out in some selected areas of Cheongju city. Literature from previous similar studies was consulted and some important factors affecting the runoff characteristics of urban drainage areas were analyzed for some selected survey points. It was found that the factors most affecting BOD are the number of dry days prior to rainfall and the intensity of the rainfall. The factor most affecting CODcr is the number of dry days prior to rainfall. The factors most affecting SS are the amount of rainfall and the number of dry days prior to rainfall. The factor most affecting TN is the amount of rainfall. The factor most affecting TP is the amount of rainfall and the number of dry days prior to rainfall.

• Korean Journal of Cognitive Science
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• v.15 no.3
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• pp.45-55
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• 2004

Immersion means the state of total devotion to what one is involved in. The typical form of this immersion experience happens when one is engaging in computer games. We analyze how the users became immersed in computer games. There are 22 elements of immersion involved in cognitive and emotional fun based cm the flow theory. After analyzing these elements with respect to flow dimension and game mechanics, we find that there are differences in the degree of their immersion in games. There are 7 elements that may be considered preferentially in designing computer games: unity, stimulation, gambling, virtual reality, fantasy, satisfaction accomplishment. We match these elements to Roget's categories and search for new categories with heading information and reference information. As a result 22 immersion elements are subdivided into 229 factors in the concrete. With these factors, we can design a multimedia game which has mon powerful immersion.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.2
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• pp.180-191
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• 2006

Objectives : The purpose of this clinical report was to investigate the general characteristics of the patients with nasal polyps and estimate the efficacy of the oriental medical treatment on nasal polyps. Methods : We performed a clinical analysis of 50 patients who visited Kabsan oriental clinic due to nasal polyps. We inquired into distribution of age, sex, operation history related to nose, grade of nasal polyps, efficacy of treatment, etc. Results and Conclusions : 1. The sex ratio was 2.3 : 1. The average age was 40.02 years. 2. In the nasal operation history, inexperienced patients were 35 cases and experienced patients were 15 cases. 3. In the region of nasal polyps, there were 35 cases of bilateral types of nasal polyps, which is mon than in unilateral types. In the number of nasal polyps, multicentric types of 26 cases were similar in the number with solitary type of 24 cases. 4. In the predisposing or concomitant diseases, chronic sinusitis was the most frequent followed by allergic rhinitis, chronic rhinitis, septal deviation chronic otitis media, asthma, tonsilitis and allergic dermatitis. 5. In the main symptoms, nasal obstruction was the most important. In the concomitant symptoms, patients had frequent rhinorrhea, smell disturbance, postnasal drip, headache, etc. 6. The average treatment period was 3,58 months and the average number of treatment was 12.94 sessions. 1. In the amount of herbal medicine, 2 and 3 Ji(劑) were the most. The most frequently used herbal medicine to treat was Hyangbujamogeuntanggagam(香附子茅根湯加減) 8. In the change of grade after treatment, Grade I was the most. In the efficacy of treatment, 'good' was the most, followed by 'excellent' and 'uneffective'.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.265-271
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• 2000

Orifice meters and turbine meters are frequently used for measuring gas flow in gas industry. However, to insure the accuracy of the measurement, a certain length of the meter run at the upstream of the flow meter is required. The objective of this study is to analyze flow measurement errors of the orifice meter quantitatively for shorter lengths of the meter runs than those suggested in the standard manuals with variation of diameter ratio( $\beta$ ratio) and flow rate and also to analyze flow measurement errors of the turbine meter with and without straightener. The test results showed that the flow measurement errors of the orifice meter were inversely proportional to the diameter ratio. In other words, when the diameter ratio is 0.3 and 0.7, the measurement error is $-7.3\%$ and $-3.5\%$, respectively. the main reason of the measurement error is due to the swirl effect from the configuration of the meter run at the upstream of the flow meter. In case the length of the meter run is shorter than that suggested In the standard, the swirl effect is not removed completely and it affects the flow meter's performance. As mentioned above, the less the pipe diameter ratio, the mon the flow measurement error. It means that the swirl effect on the orifice meter increases as the $\beta$ ratio decreases.

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.45-51
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• 2008

Recently, the demand of ultra high-rise building is on the increase in korea due to the rapidly changing movement in economic growth and the expansion of national infrastructure. At the same time, the tendency toward the amount used of concrete has greatly increased every year. In addition, as the seriousness of quantity demanded of aggregate is gathering strength, the active areas of research proceeds to do actively in every place in order to review the usability of crushed sand as a part of the countermeasures. And, it needs to establish the quality standard and service guide, etc. for the practical use. Accordingly, this study was to establish the ratio of water-binder materials as three levels like 23.5, 27.5, and 31.5%, and the replacement ratio as three levels like 0, 50, and 100% in order to define the engineering properties of ultra high-strength concrete using the crushed sand. This study was to examine it after establishing the combined condition by the substitute of the fine aggregate percentage and admixture. From the result of this research above, it may be summed up as follows. 1) The more the replacement ratio of crushed sand and the ratio of water-binder materials increased, the mon the fluidity decreased due to the decrease of irregular grain shape of sand and unit combined discretion. 2) This study found out that 100% of replacement ratio of crushed sand was almost similar level to the compressive strength of concrete using the natural sand.

• Journal of Chest Surgery
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• v.35 no.2
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• pp.137-140
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• 2002

Aortic regurgitation in the pediatrics who had previous cardiac surgery is increased with their improved longterm survival rate and their complexity of heart disease. So the need of aortic valve surgery in pediatrics is also on the increase. A 10-year old boy was admitted for progressive cyanosis and dyspnea on exertion(DOE). The patient had been underwent lateral tunnel Fontan operation before. Echocardiography and cardiac catheterization study revealed hepatic vein drained to pulmonary atrium via intrahepatic collaterals, moderate atrioventricular regurgitation, and severe aortic regurgitation due to aortic root dilation. We report a case who had aortic root reconstruction, valvuloplasty of the atrioventricular valve, and hepatic vein ligation successfully Cyanosis and DOE was dramatically improved after the operation

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.310-317
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• 2005

In opposition to conventional networks, mobile ad hoc networks usually do not offer trust about nodes or online access through certificate authorities or centralized servers. But, nodes in those systems need process that can search path as well as trust each other to exchange data in safety For these reasons, traditional security measures that require online trusted authorities or certificate storages are not well-suited for securing ad hoc networks. In this paper, I propose a secure and effective method to search the optimized path using profitable flooding techniques on certificate chains in MANETS(Mobile Ad hoc NETworks). This system includes not only using routing protocols that are generally broadcasting packets but also finding nodes securely and verifing the process through tiust relationships between nodes that are searched.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.9
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• pp.745-751
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• 2012

Hybrid rocket shows interesting characteristics of complicated mixing layers developed by interactions between turbulent oxidizer flow and mass flow from surface due to fuel vaporization. In this study, compressible LES with a ring structure attached at the entrance of the combustor are performed. According to one recent report, adding a ring structure in the middle of the combustor helps increasing regression rate. From the numerical results, it is seen that vortex structures near the wall becomes stronger due to the interaction with surface mass injection, and the local heat flux increases due to the vortices. This phenomenon is obviously related to the generation of dimple structures which are seen in the number of experiments. Also, the ring structure at the entrance induces strong vortex flow which enhances heat transfer to the wall surface and mixing between fuel and oxidizer as well as reaction efficiency.