• Corrosion Science and Technology
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• v.15 no.1
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• pp.6-12
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• 2016

Flow-Accelerated Corrosion (FAC) is a well-known degradation mechanism that attacks the secondary piping in nuclear power plants. Since the Surry Unit 2 event in 1986, most nuclear power plants have implemented management programs to deal with damages in carbon and low-alloy steel piping. Despite the utmost efforts, damage induced by FAC still occurs in power plants around the world. In order to predict FAC wear, some computer programs were developed such as CHECWORKS, CICERO, and COMSY. Various data need to be input to these programs; the chemical composition of secondary piping, flow operating conditions and piping geometries. CHECWORKS, developed by the Electric Power Research Institute (EPRI), uses a geometry code to calculate geometry effects. Such a relatively simple geometry code is limited in acquiring the accuracy of FAC prediction. Recently, EPRI revisited the geometry code with the intention of updating it. In this study, numerical simulations were performed for two adjacent $90^{\circ}$ elbows and the results were analysed in terms of the proximity effect between the two adjacent elbows.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.952-964
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• 2016

The prototype generation IV sodium-cooled fast reactor (PGSFR) has been developed by the Korea Atomic Energy Research Institute. This reactor uses sodium as a reactor coolant to transfer the core heat energy to the turbine. Sodium has chemical characteristics that allow it to violently react with materials such as a water or steam. When a sodium-water reaction (SWR) occurs due to leakage or breakage of steam generator tubes, high-pressure waves and corrosive reaction products are produced, which threaten the structural integrity of the components of the intermediate heat-transfer system (IHTS) and the safety of the primary heat-transfer system (PHTS). In the PGSFR, SWR events are included in the design-basis event. This event should be analyzed from the viewpoint of the integrities of the IHTS and fuel rods. To evaluate the integrity of the IHTS based on the consequences of the SWR, the behaviors of the generated high-pressure waves are analyzed at the major positions of a failed IHTS loop using a sodium-water advanced analysis method-II code. The integrity of the fuel rods must be consistently maintained below the safety acceptance criteria to avoid the consequences of the SWR. The integrity of the PHTS is evaluated using the multidimensional analysis of reactor safety-liquid metal reactor code to model the whole plant.

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.23-36
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• 2018

Discrete Event System Specification (DEVS) has been used for decades as it provides sound semantics for hierarchical modular specification of discrete event systems. Instead of the mathematical specification, the DEVS diagram, based on the structured DEVS formalism, has provided more intuitive and convenient representation of complex DEVS models. This paper proposes a clean room process for implementation and verification of a DEVS diagram model specification into a simulation software source code. Specifically, it underlies a sequence of transformation steps from conformance and integrity checking of a given diagram model, translation into a corresponding tabular model, and finally conversion to a simulation source code, with each step being inversely verifiable for traceability. A simple example helps developers to understand the proposed process with associated transformation methods; a case study shows that the proposed process is effective for and adaptable to practical simulation software development.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.17-24
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• 2011

The Youth Olympic Games(YOG) is an international multi-sport event first held in Singapore from August 14 to August 26, 2010. The idea for such an event was introduced by International Olympic Committee(IOC). The Federation of International Gymnastics(2009) designed the Code of Points and regulates for junior gymnastics at this time. The purpose of this study was to give crucial information and adapt to coaches and junior gymnasts at the time of changing code rapidly. For this study, The eight finalists rings exercise at the 1st Youth Olympic Games was recorded using a digital camcoder. The exercise contents analysis of rings was carried out by an experienced international judge using Code of Points(FIG, 2009). The C elements in various difficulties were performed the highest frequency. The elements group I was the most frequently performed in overall difficulties. Moreover, All the gymnasts performed the elements of the Jonasson and Yamawaki in Group I. Therefore, junior gymnasts need to consider Jonasson and Yamawaki elements correctly in elements group I. The 1st ranked ROU(132) gymnast performed high difficulty value for his routine with the highest E score(9.050). The average of D score were 5.125. In the E scores, 8th USA(140) gymnast received the lowest E score of 8.15, 5th MGL(127) gymnasts received the fewer E score of 8.475. Coaches and junior gymnasts should try to increase D score above 5.125 by higher swing elements in Group I and II as well, decrease deduction of elements in exercise contents.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.13-27
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• 2017

This paper presents a tool that automatically generates mobile web applications from user interface (UI) models which are based on PELUM (Pattern and Event based Logical User Interface Modeling). PELUM is a method for the effective development of UI-centered embedded systems via UI modeling. The proposed tool consists of a model editor and a code generator. The former provides an environment for modeling a Logical UI Model (LUM) and a Programming Interface Model (PIM) on the web. On the other hand, the code generator sets the screen configuration and events' behavior, according to the LUM, synthesizing a local database schema according to the PIM, and then generates an executable mobile web app. It also can produce mashup web apps by receiving an open API address via the PIM. The generated mobile web apps follow the Model-View-Controller (MVC) architecture in order for users to easily customize them. The proposed tool enables them to generate mobile web apps that can be executed on various devices by modeling logical UIs on the web.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.83-92
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• 2009

Complicated business logic makes program complexity more complicated. It's inevitable that the program must undergo reengineering processes all the way of in its lifetime. Hot spot analysis that has diverse purposes is getting an important question more and more. As a rule, reengineering process is done by UML model-based approach to analyze the legacy system. The smallest fragment of targets to be analysed is unit, that is function or class. Today's software development is to deal with huge change of software product and huge class including heavy quantity of LOC(Lines Of Code). However, analysis of unit is not precise approach process for reliable reengineering consequence. In this paper, we propose very precise hot spot analysis approach using Aspect-Oriented Programming languages, such as AspectJ. Typically the consistency between UML and source is needed code to redefine the modified library or framework boundaries. But reengineering approach using AOP doesn't need to analyze UML and source code. This approach makes dynamic event log data that contains detailed program interaction information. This dynamic event log data makes it possible to analyze hot spot.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.17-30
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• 2015

Unlike existing widely used bytecode-centric Android application code obfuscation methodology, our scheme in this paper makes encrypted file i.e. DEX file self-extracted arbitrary Android application. And then suggests a method regarding making the loader app to execute encrypted file's code after saving the file in arbitrary folder. Encrypted DEX file in the loader app includes original code and some of Manifest information to conceal event treatment information. Loader app's Manifest has original app's Manifest information except included information at encrypted DEX. Using our scheme, an attacker can make malicious code including obfuscated code to avoid anti-virus software at first. Secondly, Software developer can make an application with hidden main algorithm to protect copyright using suggestion technology. We implement prototype in Android 4.4.2(Kitkat) and check obfuscation capacity of malicious code at VirusTotal to show effectiveness.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.819-828
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• 2009

This paper suggests to standardize railway accident restoration types as the code and standard operation system for efficient railway accident management. First of all, the damage types of have been carefully analyzed and reclassified. This study suggested the combination of 3 distinct code factors: restoration class, restoration object, and restoration location to standardize them. In addition, this study suggested procedures to make the standard operation system of emergency restoration, defined the worst case of emergency restoration and the important events. Therefore, the standard operation system of emergency restoration is developed. It shall play a major role as the database system for railway accident management, minimum of damage and rapid control of accident.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.3-10
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• 2010

The present study aims to investigate neural activations according to the level of code switching in English proficient bilinguals and to find the relationship between the performance of language switching and proficiency level using ERPs (event-related potentials). First, when comparing high-proficient (HP) with low-proficient (LP) bilingual performance in a native language environment, the activation level of N2 was observed to be higher in the HP group than in the LP group, but only under two conditions: 1) the language switching (between-language) condition known as indexing attention of code switching and 2) the inhibition of current language for L1. Another effect of N400 can be shown in both groups only in the language non-switching (within-language) condition. This effect suggests that both groups completed the semantic acceptability task well in their native language environment without the burden of language switching, irrespective of high or low performance. The latencies of N400 are only about 100ms earlier in the HP group than in the LP group. This difference can be interpreted as facilitation of the given task. These results suggest that HP showed the differential activation in inhibitory system for L1 in switching condition of L1-to-L2 to be contrary to inactivation of inhibitory system for the LP group. Despite the absence of an N400 effect at the given task in both groups, differential latencies between the peaks were attributed to the differences of efficiency in semantic processing.

• Nuclear Engineering and Technology
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• v.28 no.3
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• pp.265-273
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• 1996

Among those tests performed during the Yonggwang Nuclear Power Plant Units 3 and 4 (YGN 3&4) Power Ascension Test period, the Loss of a Main Feedwater Pump test at l00% power is one of the major test which characterize the capability of YGN 3&4. In this event, one of the two normally operating main feedwater pumps is tripped resulting in a 50% reduction in the feedwater flow. Unless the NSSS and Turbine/Generator control systems actuate properly, the reactor will be tripped on low SG water level or high pressurizer pressure. The test performed at Unit 3 was successful by meeting all acceptance criteria, and the plant was stabilized at a reduced power level without reactor trip. The measured test data for the major plant parameters are compared with the predictions made by the KISPAC computer code, an updated best-estimate plant performance analysis code, to verify and validate its applicability. The comparison results showed good agreement in the magnitude as well as the trends of the major plant parameters. Therefore, the KISPAC code can be utilized for the best-estimate nuclear power plant design and simulation tool after a further verification using other plant test data.