• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.239-246
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• 2017

There are various transversal structures (small dams or drop structures) in median and small streams in Korea. Most of them are concrete structures and it is so hard to exclude low-level water. Unless drainage valves and/or gates would not be installed near bottom of bed, sediment from upstream should be deposited and also contaminants attached to the sediments would devastatingly threaten the water quality and ecosystem. One of countermeasures for such problem is the bypass pipe installed underneath the transversal structure. However, there is still issued whether it would be workable if the gravels and/or stones would roll into and be not excluded. Therefore, in this study, the conditions to exclude the rip stone which enter into the bypass pipe was reviewed. Based on sediment transport phenomenon, the behavior of stones was investigated with the concepts from the critical shear stress of sediment and d'Alembert principle. As final results, the basis condition (${\tau}_c{^*}$) was derived using the Lagrangian description since the stones are in the moving state, not in the stationary state. From hydraulic experiments the relative velocity could be obtained. In order to minimize the scale effect, the extra wide channel of 5.0 m wide and 1.0 m high was constructed and the experimental stones were fully spherical ones. Experimental results showed that the ratio of flow velocity to spherical particle velocity was measured between 0.5 and 0.7, and this result was substituted into the suggested equation to identify the critical condition wether the stones were excluded. Regimes about the exclusion of stone in bypass pipe were divided into three types according to particle Reynolds number ($Re_p$) and dimensionless critical shear force (${\tau}_c{^*}$) - exclusion section, probabilistic exclusion section, no exclusion section. Results from this study would be useful and essential information for bypass pipe design in transveral structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.125-132
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• 2017

The development project of Busan New Port aims to be Logistics Hub Port but there are too many things to deal with ; enlargement of harbour, interport competition, modernization of harbour loading equipment and so on. At present, 23 berths of North and South container quay are in operation and 22 berths will be constructed on west and south-side by 2020. Namely, Busan New Port will operate 45 berths in 2020. When it comes to port distripark, a large-scale of Port distripark project is underway, such as Ung-Dong district 1,2 phase, West container 1,2phase, North distripark and so on. This study is to deduce traffic system problem of Busan New Port which is caused by the development project through predicting traffic need considering the development project. According to study, there are three main problems of traffic system : 1. traffic congestion caused on main crossroad, connecting second harbour back road. 2. It has been predicted that South-North road and traffic capacity of New Port road would lack compared to traffic volume-to-be-increased. Moreover, the detour volume of traffic is caused because New Port's 1st avenue and route 2 were not connected directly. Thus, this study suggests three kinds of improvement plan for smoother traffic flow. 1st. Operate roundabout on major intersection, for example, second harbour back road, west container wharf's subway corridors(South to North), and permit only right turn on sub-intersection. 2nd. Extend New Port road(North container's port road) by utilizing side walk and median. 3rd. Install exit ramp which utilizes Route 2 connecting New Port's 1st avenue and local road 1042. The method we used to analyze the effect of improvement is Vissim of Mircro Simulation Package.

• Progress in Medical Physics
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• v.25 no.4
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• pp.298-303
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• 2014

In this study, we examine the trends and types of incidents frequently occur during radiation therapy by using the data from the radiation oncology safety information system (ROSIS), according to discovery method explores the development direction of future research accident cause factor control method. This study was carried out analysis of incident data in ROSIS nearly 1163 cases in last 11 years from 2003 to 2013. We categorized into treatment methods, found the time, discoverer of occupations and finding ways to analyze the data. Then, we calculate the percentage and the classification for each item. About 1163 cases of incident cases including the near miss cases, external radiation therapy, brachytherapy and other were 97%, 2% and 1%. In the case was improperly planned dose delivery was 44% (497 cases) which 429 cases (86%) was found before 3 fractions and 13 cases were found after 11 fractions. The investigation was found to be distributed in various a found times. Approximately 42% of found time was during treatment and 29% of patients were found the problem during inspection chart. Occupation to discover the most radiation accidents was the radiation therapist (53%) who works in treatment room. Among 1163 incidence cases, 24% cases were found the accident before the treatment, therefore most of accident were found after of during the treatment (70%, 813 cases). This trend is acquired through ROSIS analysis, is expected to be not significantly different in the case of Korea, so it is necessary more diverse and systematic research for the prevention and early detection by using the ROSIS data.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.125-135
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• 2009

Statement of problem: Loosening or fracture of the abutment screw is one of the common problems related to the dental implant. Generally, in order to make the screw joint stable, the preload generated by tightening torque needs to be increased within the elastic limit of the screw. However, additional tensile forces can produce the plastic deformation of abutment screw when functional loads are superimposed on preload stresses, and they can elicit loosening or fracture of the abutment screw. Therefore, it is necessary to find the optimum tightening torque that maximizes a fatigue life and simultaneously offer a reasonable degree of protection against loosening. Purpose: The purpose of this study was to present the influence of tightening torque on the implant-abutment screw joint stability with the 3 dimensional finite element analysis. Material and methods: In this study, the finite element model of the implant system with external butt joint connection was designed and verified by comparison with additional theoretical and experimental results. Four different amount of tightening torques(10, 20, 30 and 40 Ncm) and the external loading(250 N, $30^{\circ}$) were applied to the model, and the equivalent stress distributions and the gap distances were calculated according to each tightening torque and the result was analyzed. Results: Within the limitation of this study, the following results were drawn; 1) There was the proportional relation between the tightening torque and the preload. 2) In case of applying only the tightening torque, the maximum stress was found at the screw neck. 3) The maximum stress was also shown at the screw neck under the external loading condition. However in case of applying 10 Ncm tightening torque, it was found at the undersurface of the screw head. 4) The joint opening was observed under the external loading in case of applying 10 Ncm and 20 Ncm of tightening torque. 5) When the tightening torque was applied at 40 Ncm, under the external loading the maximum stress exceeded the allowable stress value of the titanium alloy. Conclusion: Implant abutment screw must have a proper tightening torque that will be able to maintain joint stability of fixture and abutment.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.105-115
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• 2008

Statement of problem: Proper finishing and polishing enhance both the esthetics and the longevity of restored teeth. Blade finishing technique would be suited for smoothing and finishing. Evaluation of this technique are necessary. Purpose: The purpose of this study was to evaluate the blade finishing and polishing procedures on the surface profile and roughness of ormocer-based composite resin and nanohybrid composite resin. Material and methods: The material included a ormocer-based composite resin ($Admira^{(R)}$ & $Admira^{(R)}$ Flow); a nanohybrid composite resin ($Grandio^{(R)}$ & $Grandio^{(R)}$ Flow). One hundred forty specimens of each group were prepared using a mylar strip and randomly divied into blade finishing and rubber polishing groups (n=10). The average surface roughness (Ra) in micrometers was measured and the surface profile was examined by scanning electron microscopy (SEM) (Magnification ${\times}$ 200). The data were analyzed by Mann-Whitney Test at 0.05 significance level. Conclusion: The results of this study indicated that the mylar strip produced the smoothest surface on all materials and among the finishing-polishing methods was not significanct difference (P>0.05). Ormocer-based flowable composite resin performedthe lowest variability in initial surface roughness among the tested materials.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.5
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• pp.909-928
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• 2020

From the early 1970s, the US government began to recognize that penetration testing could not assure the security quality of products. Results of penetration testing such as identified vulnerabilities and faults can be varied depending on the capabilities of the team. In other words none of penetration team can assure that "vulnerabilities are not found" is not equal to "product does not have any vulnerabilities". So the U.S. government realized that in order to improve the security quality of products, the development process itself should be managed systematically and strictly. Therefore, the US government began to publish various standards related to the development methodology and evaluation procurement system embedding "security-by-design" concept from the 1980s. Security-by-design means reducing product's complexity by considering security from the initial phase of development lifecycle such as the product requirements analysis and design phase to achieve trustworthiness of product ultimately. Since then, the security-by-design concept has been spread to the private sector since 2002 in the name of Secure SDLC by Microsoft and IBM, and is currently being used in various fields such as automotive and advanced weapon systems. However, the problem is that it is not easy to implement in the actual field because the standard or guidelines related to Secure SDLC contain only abstract and declarative contents. Therefore, in this paper, we present the new framework in order to specify the level of Secure SDLC desired by enterprises. Our proposed CIA (functional Correctness, safety Integrity, security Assurance)-level-based security-by-design framework combines the evidence-based security approach with the existing Secure SDLC. Using our methodology, first we can quantitatively show gap of Secure SDLC process level between competitor and the company. Second, it is very useful when you want to build Secure SDLC in the actual field because you can easily derive detailed activities and documents to build the desired level of Secure SDLC.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.3
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• pp.128-136
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• 2018

This study was centered on the protested data of the issue of "History of Landscape Architecture" in the handwritten course of landscaping articles of National Qualifications Test. The purpose of this study is to examine the types of social problems in the process of correcting erroneous historical facts. The purpose of this study was to find alternatives for the development of the field of landscape and culture history that can assist in the verification of the historical facts of the landscape sciences examination questions. The main results are as follows. First, as a result of analyzing the contents of the landscape architects' subject matter, the establishment of concept of landscape style and form and the confirmation of historical facts were investigated as important types to be established for development of landscape landscape history department. It seems that the social consensus of the expert group is needed to supplement the lack of data to refer to landscape architectural theory. Second, the analysis of the problematic narrative contents resulted in a total of five types of questionnaires. The appeared in the Undefined style and form(52.94%), Unproven historical facts(25.13%), Obscurity Era classification(11.77%), Lack of specificity(6.95%), Content scope of obscurity events(3.21%) Third, it is not only the lack of information to learn the theory by comparing and analyzing the contents of the statements in the landscape architect 's question items, but also the difference of contents between books was analyzed as the main cause of the problem. As a result of examining the characteristics and examples of the issues raised in landscape architectural problems, it was related to the social phenomenon, and it was classified into cultural factors and political factors. Fourth, the resolution of problematic issues in landscape architects' landscaping articles, which are national technical qualification tests, shows positive results. The information determined in the process of solving the perceived content can be used directly in landscaping field, and it helps the accuracy of the verification process by identifying the types and characteristics of the issues.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.11
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• pp.509-520
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• 2015

College Scholastic Ability Test(CSAT) is a primary test to evaluate the study achievement of high-school students and used by most universities for admission decision in South Korea. Because its level of difficulty is a significant issue to both students and universities, the government makes a huge effort to have a consistent difficulty level every year. However, the actual levels of difficulty have significantly fluctuated, which causes many problems with university admission. In this paper, we build two types of data-driven prediction models to predict correct answer rate and to identify significant factors for CSAT English test through accumulated test data of CSAT, unlike traditional methods depending on experts' judgments. Initially, we derive candidate question-specific factors that can influence the correct answer rate, such as the position, EBS-relation, readability, from the annual CSAT practices and CSAT for 10 years. In addition, we drive context-specific factors by employing topic modeling which identify the underlying topics over the text. Then, the correct answer rate is predicted by multiple linear regression and level of difficulty is predicted by classification tree. The experimental results show that 90% of accuracy can be achieved by the level of difficulty (difficult/easy) classification model, whereas the error rate for correct answer rate is below 16%. Points and problem category are found to be critical to predict the correct answer rate. In addition, the correct answer rate is also influenced by some of the topics discovered by topic modeling. Based on our study, it will be possible to predict the range of expected correct answer rate for both question-level and entire test-level, which will help CSAT examiners to control the level of difficulties.

• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.67-74
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• 2014

Recently, the number of road construction is increasing by industrial development. According to this industrial tendency, the number of traffic accidents are consistently increasing due to increasing number of vehicle on the road. This is mainly because traffic accidents are occurred by various parameter such as negligence of driver, vehicle defects, state of unstable road, natural environment etc. Lane department of vehicles from guardrail is occurring frequently. This type of accident is caused by vehicle performance improvement and shape of vehicle, weak guardrail installation and maintenance. Guardrail has the purpose on prevention such as prevention of traffic accident and prevention of deviating out of road, minimizing damage of driver and vehicle by collision as well as entry into the road through guardrail. Stability evaluation test of guardrail verifies the behavior of guardrail through the crash of truck. At this time, the crash condition has 100 km/h of velocity and $15^{\circ}$ of impact angle. In the case of ground condition, filling slope condition has relatively high bearing capacity of infinite ground towards the test. Guardrail is generally installed on road of shoulder in fill slope in korea. It is possible for stability problem to deteriorate ground bearing capacity in Guardrail in fill slope. The existed study towards stability of guardrail has been carried out in the infinite ground. However, the study on the behavior of fill slope with guardrail is not performed by vehicle collision. Therefore, In this study, the numerical analysis using LS-DYNA was executed for verification on behavior of fill slope with guardrail through vehicle collision. This numerical analysis was carried out with change of embedded depth on installed guardrail post in shoulder of fill slope by vehicle collision and 8 tonf truck crash providing at NCAN (National Crash Analysis Center). As the result, displacement and stress on fill slope are decreased in accordance with the increase of embedded depth of guardrail post. Ground bearing capacity is deteriorated at depth of 450 mm form shoulder of road on fill slope.

• The Journal of Korean Philosophical History
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• no.31
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• pp.87-111
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• 2011

In moral instruction, one of the important purposes is cultivate students' meaningful moral knowing. To obtain this purpose, generally systems approach has been adopted and used in moral instruction. Systems approach has emphasized efficient designs which do not occur incidental learning that does not contribute to obtain learning objectives. However, moral meaning may occur to the subject of knowing, then occurrence of coincidence can not be excluded. If we approach to moral instruction with operative and engineering ways, we may convey the learning object but it won't be received meaningfully. Because of such problem, moral instruction has been required an alternative perspective contrary to the systems approach. Above all we need to reconsider the logic of explanation based on the systems approach. Because the moral instruction is understood that it is a systematic and operative act according to the logic of explanation. According to the logic of explanation, education is an act that conveys the teachers' knowledge to students who have inferior knowledge to teachers'. During this process, students' interpretation has been overlooked. In moral instruction, the teachers' interpretation of moral meaning can occur and extend by students' interpretation. When we understand moral instruction as the course of alliance between interpretation, it could be stood out that teaching as a symbol, constitution of teaching text as a vacuum, learning as a coincidence. When we stand out these aspects, the moral instruction could be understand as a poetic act. And based on such understanding, we can abstract specific resemblances between the poetic act and the moral instruction. There are semantic invariants and semantic variants in the teaching text of moral instruction. The semantic variants premise uncertainty. The limitation, that is, semantic invariants and the openness which is possible within semantic variants are changed to the moral instruction by students' response. It is essential that a selective attention as esthetic transaction that could be changed from text to poet. Like this, we need to take notice of instructive aspects not to means for reaching learning objectives but to act for being possible disinterested experiential learning.