• Korean Journal of Construction Engineering and Management
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• v.21 no.3
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• pp.20-27
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• 2020

EPC contractors have made continuous efforts to develop integrated project execution methods to improve the performance of industrial plant project. In particular, the concept of Advanced Work Packaging (AWP) has been recently presented by readjusting the existing "Work Packaging" concept as part of the integrated project execution method from the project life-cycle perspective. However, Korean EPC contractors are still unfamiliar with the AWP implementation. Thus, this study aims to identify the organizational competency factor for effective implementation of AWP. For this purpose, first, this study identified the expected risks in AWP project and the 29 organizational competency factors to manage risks. Second, five experts verified the suitability of factors and supplemented the factors. Finally, 37 factors were identified as organizational competency factors for implementing AWP.

• The Mathematical Education
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• v.26 no.2
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• pp.9-13
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• 1988

Mathematics education is generally to cultivate mathematical thought. Most meaningful thought is to solve a certain given situation, that is, a problem. The aim of mathematies education could be identified with the cultivation of mathematical problem-solving ability. To cultivate mathematical problem-solving ability, it is necessary to study the nature of mathematical ability and its aspects pertaining to problem-solving ability. The purpose of this study is to investigate the relation between problem-solving ability and classficational viewpoint of mathematical verbal problems, and bet ween the detailed abilities of problem-solving procedure and classificational viewpoint of mathematical verbal problems. With the intention of doing this work, two tests were given to the third-year students of middle school, one is problem-solving test and the other classificational viewpoint test. The results of these two tests are follow ing. 1. The detailed abilities of problem-solving procedure are correlated with each other: such as ability of understanding, execution and looking-back. 2. From the viewpoint of structure and context, students classified mathematical verbal problems. 3. The students who are proficient at problem-solving, understanding, execution, and looking-back have a tendency to classify mathematical verbal problems from a structural viewpoint, while the students who are not proficient at the above four abilities have a tendency to classify mathematical verbal problems from a contextual viewpoint. As the above results, following conclusions can be made. 1. The students have recognized at least two fundamental dimensions of structure and context when they classified mathematical verbal problems. 2. The abilities of understanding, execution, and looking- back effect problem-solving ability correlating with each other. 3. The instruction emphasizing the importance of the structure of mathematical problems could be one of the methods cultivating student's problem-solving ability.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.3
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• pp.115-124
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• 2005

When the application code is downloaded into the mobile device, it is important to provide authentication. Usually, mobile code execution is overlapped with downloading to reduce transfer delay. To the best of our knowledge, there has not been any algorithm to authenticate the mobile code in this environment. In this paper, we present two efficient code authentication schemes that permit overlapping of execution and downloading under the two cases: the first is when the order of transmission of code chunks is determined before the transmission and the second is when this order is determined during the transmission. The proposed methods are based on hash chaining and authentication trees, respectively. Especially, the latter scheme utilizes previously received authentication informations to verify the currently received chunk, which reduces both communication overhead and verification delay. When the application code consists of n chunks, communication overheads of the both schemes are 0(n) and verification delays of these two schemes are O(1) and O(log n), respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.1008-1012
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• 2009

Obfuscation is known as one of the most effective methods to protect software against malicious reverse engineering transforming the software into more complicated one with still preserving the original semantic. However, obfuscating a program can increase both code size of the program and execution time compared to the original program. In mobile devices, the increases of code size and execution time incur the waste of resources including the increase of power consumption. This paper has analyzed the effectiveness of some high-level obfuscation algorithms as well as their power consumption with implementing them under an embedded board equipped with ARM processor. The analysis results show that there is (are) an efficient obfuscation method(s) in terms of execution time or power consumption according to characteristics of a given program.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.261-274
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• 1999

Recently, automated business processing systems, so called workflow systems, have been studied. have been studied. even though each task has noticible duration inherently, most of previous models regard it as a simple finite automation where state transitions occur instantly. In this paper, we propose a modeling method for workflow each of whose component task has minimum processing time and due-date. Firstly we provide a priority function to choose the proper alternatives when tasks fail before their due-date. The priority function considers the time-relevant factor and the semantic compatibility level to decide the best alternative. secondly, we identify six different types of execution requirements for tasks with noticible durations. They are serial, parallel, simultaneous start simultaneous termination, interleaved and nested dependency. Note that previous models deal with only serial execution and parallel execution. Lastly, we also propose graph-based methods to detect logical conflicts in time constraint-based workflow specifications.

• Journal of the Korea Society of Computer and Information
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• v.26 no.9
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• pp.1-12
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• 2021

In this paper, we propose a tool called ARCAV (Atomatic Recovery of CUDA Atomicity violation) to automatically repair atomicity violations in GPU (Graphics Processing Unit) program. ARCAV monitors information of every barrier and memory to make actual memory writes occur at the end of the barrier region or to make the program execute barrier region again. Existing methods do not repair atomicity violations but only detect the atomicity violations in GPU programs because GPU programs generally do not support lock and sleep instructions which are necessary for repairing the atomicity violations. Proposed ARCAV is designed for GPU execution model. ARCAV detects and repairs four patterns of atomicity violations which represent real-world cases. Moreover, ARCAV is independent of memory hierarchy and thread configuration. Our experiments show that the performance of ARCAV is stable regardless of the number of threads or blocks. The overhead of ARCAV is evaluated using four real-world kernels, and its slowdown is 2.1x, in average, of native execution time.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1487-1503
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• 2019

The methods and performance of a pin-level nuclear reactor core thermal-hydraulics (T/H) code ESCOT employing the drift-flux model are presented. This code aims at providing an accurate yet fast core thermal-hydraulics solution capability to high-fidelity multiphysics core analysis systems targeting massively parallel computing platforms. The four equation drift-flux model is adopted for two-phase calculations, and numerical solutions are obtained by applying the Finite Volume Method (FVM) and the Semi-Implicit Method for Pressure-Linked Equation (SIMPLE)-like algorithm in a staggered grid system. Constitutive models involving turbulent mixing, pressure drop, and vapor generation are employed to simulate key phenomena in subchannel-scale analyses. ESCOT is parallelized by a domain decomposition scheme that involves both radial and axial decomposition to enable highly parallelized execution. The ESCOT solutions are validated through the applications to various experiments which include CNEN $4{\times}4$, Weiss et al. two assemblies, PNNL $2{\times}6$, RPI $2{\times}2$ air-water, and PSBT covering single/two-phase and unheated/heated conditions. The parameters of interest for validation include various flow characteristics such as turbulent mixing, spacer grid pressure drop, cross-flow, reverse flow, buoyancy effect, void drift, and bubble generation. For all the validation tests, ESCOT shows good agreements with measured data in the extent comparable to those of other subchannel-scale codes: COBRA-TF, MATRA and/or CUPID. The execution performance is examined with a mini-sized whole core consisting of 89 fuel assemblies and for an OPR1000 core. It turns out that it is about 1.5 times faster than a subchannel code based on the two-fluid three field model and the axial domain decomposition scheme works as well as the radial one yielding a steady-state solution for the OPR1000 core within 30 s with 104 processors.

• Journal of Korean society of Dental Hygiene
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• v.22 no.1
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• pp.21-28
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• 2022

Objectives: This study investigated the influence of oral exercise programs with whole-body exercises on the mental health of the elderly. Methods: Elderly individuals aged 65 years or older were assigned to an experimental group and a control group. Oral exercises with whole-body exercises were conducted in the experimental group for 40 minutes, twice weekly, during 5 weeks from May to June 2021. To evaluate the effectiveness of the program, the oral health related quality of life (OHIP-14, GOHAI), mental health, happiness, and social support of the elderly were explored both before and after the execution of the program in the experimental group. A paired sample t-test was performed to check the changes in the factors investigated, both before and after the execution of the program in the two groups. Results: The values of difference between the experimental and control group were compared in relation to the dependent variables, before and after the execution of the oral exercise program with the whole-body exercises. It was found that statistically significant differences in the OHIP-14 (p=0.163), GOHAI (p=0.156), and feelings of happiness in the elderly (p=0.280) were not evident in the experimental group. However, statistically significant differences emerged with regard to the mental health and provision of social support of the elderly (p<0.05). Conclusions: It was found that the oral exercise program with whole-body exercises executed in this study were effective in improving the mental health and social support of the elderly. However, no significant differences were shown in oral health relating to quality of life and feelings of happiness. It is considered that these findings need to be verified by means of future long-term studies.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.253-266
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• 2023

The Null Pointer Dereference vulnerability is a significant vulnerability that can cause severe attacks such as denial-of-service. Previous research has proposed methods for detecting vulnerabilities, but large and complex programs pose a challenge to their efficiency. In this paper, we present a lightweight tool for detecting specific functions in large binaryprograms through symbolizing variables and emulating program execution. The tool detects vulnerabilities through data dependency analysis and heuristics in each execution path. While our tool had an 8% higher false positive rate than the bap_toolkit, it detected all existing vulnerabilities in our dataset.

• Smart Media Journal
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• v.12 no.5
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• pp.58-64
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• 2023

In Logic Bomb, the conditions of branch statements that trigger malicious behavior cannot be detected in advance, making Android malicious app analysis difficult. Various studies have been conducted to detect potentially suspicious branch statements that can be logic bombs and triggers, but suspicious branch statements cannot be properly detected in apps that contain information determined at runtime, such as reflection. In this paper, we propose a tool that can detect suspicious branch statements even when reflection is used in Android apps. It works through recording app execution logs and analyzing the recorded log). The proposed tool can check the relationship between the called method and the branch statement by recording and analyzing the user-defined methods, Java APIs called and method information called through reflection, and branch information in the log while the Android app is running. Experimental results show that suspicious branch statements can be detected even in apps where reflection is used.