• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.73-76
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• 2015

최근 스마트 단말을 통한 유해 콘텐츠의 보급이 확산되면서 스마트 단말에서 유해 콘텐츠를 차단하기 위한 소프트웨어의 필요성이 증가하고 있다. 이에 본 논문에서는 안드로이드 기반 스마트 단말에서 실행 이벤트의 분석을 통하여 유해 콘텐츠를 탐지 할 수 있는 방법을 제안한다. 본 논문에서는 안드로이드기반 스마트 단말에서 스트리밍 서비스가 실행되는 구조 및 관련 실행 이벤트들의 연관성을 분석하였으며, 분석 결과를 토대로 스마트 단말에서 유해 콘텐츠의 실행 여부를 판단할 수 있는 소프트웨어를 개발하였다.

• Structural Engineering and Mechanics
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• v.15 no.3
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• pp.285-297
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• 2003

Complementing recent advances made in the field of structural health monitoring and damage detection, the concept of a wireless sensing network with distributed computational power is proposed. The fundamental building block of the proposed sensing network is a wireless sensing unit capable of acquiring measurement data, interrogating the data and transmitting the data in real time. The computational core of a prototype wireless sensing unit can potentially be utilized for execution of embedded engineering analyses such as damage detection and system identification. To illustrate the computational capabilities of the proposed wireless sensing unit, the fast Fourier transform and auto-regressive time-series modeling are locally executed by the unit. Fast Fourier transforms and auto-regressive models are two important techniques that have been previously used for the identification of damage in structural systems. Their embedment illustrates the computational capabilities of the prototype wireless sensing unit and suggests strong potential for unit installation in automated structural health monitoring systems.

• Journal of The Korean Association of Information Education
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• v.2 no.2
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• pp.269-277
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• 1998

In most of the distributed deadlock detection algorithms using messages called probes, only a portion of the generated messages are effectively used, and hence the wasted probes cause heavy communication traffic. In this paper, a distributed deadlock detection algorithm is proposed which can efficiently detect deadlocks making use of those residue probes. Our algorithm is complete in the sense that they detect not only those deadlocks in which the initiator is involved as most other algorithms do, but all the other deadlocks that are present anywhere in a connected wait-for-graph. To detect all the deadlocks, the algorithms known to be most efficient require O(ne) messages, where e and n are the number of edges and nodes in the graph, respectively. The single execution of the presented algorithm can accomplish the same task with O(e) messages.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.52-54
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• 2015

In this paper we propose a new background motion compensation method which can be applicable to moving object detection with a moving monocular camera. To estimate the background motion, a series of image warpings are carried out for each pair of the corresponding patches, defined by the fixed-size lattice, based on the motion information extracted from the feature points surrounded by the patches and the estimated camera motion. Experiment results proved that the proposed has approximately 50% faster in execution time and 8dB higher in PSNR comparing to a conventional method.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1566-1574
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• 2019

Maximum power point tracking (MPPT) under the partial shading condition is a challenging research topic for photovoltaic systems. Shaded photo-voltaic module result in complex peak patterns on the power versus voltage curve which can misguide classical MPPT algorithms. Thus, various kinds of global MPPT algorithms have been studied. These have typically consisted of partial shading detection, global peak search and MPPT. The conventional partial shading detection algorithm aims to detect all of the occurrences of partial shading. This results in excessive execution of global peak searches and discontinuous operation of the MPPT. This in turn, reduces the achievable power for the PV module. Based on a theoretical investigation of power verse voltage curve patterns under various partial shading conditions, it is realized that not all the occurrences of partial shadings require a global peak search. Thus, an intelligent partial shading detection algorithm that provides exact identification of global peak search necessity is essential for the efficient utilization of solar energy resources. This paper presents a new partial shading determinant algorithm utilizing adaptive threshold levels. Conventional methods tend to be too sensitive to sharp shading patterns but insensitive to smooth patterns. However, the proposed algorithm always shows superb performance, regardless of the partial shading patterns.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.170-175
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• 2022

Reactive failure management techniques are required to mitigate the impact of errors in high performance computing. Checkpoint is the standard recovery technique for coping with errors. An application employing checkpoints periodically saves its state, so that when an error occurs while some task is executing, the application is rolled back to its last checkpointed task and resumes execution from that task onward. In this paper, assuming the time-to-errors are independent each other and generally distributed, we analyze the checkpointing model with instantaneous error detection. The conventional assumption that two or more errors do not take place between two consecutive checkpoints is removed. Given the checkpointing time, down-time, and recovery time, we derive the reliability of the checkpointing model. When the time-to-error follows an exponential distribution, we obtain the optimal checkpointing interval to achieve the maximum reliability.

• Journal of Software Assessment and Valuation
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• v.17 no.1
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• pp.41-50
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• 2021

Many game and financial apps have emulator detection functionality to defend against dynamic reverse engineering attacks. However, existing Android emulator detection methods have limitations in detecting the latest mobile game emulators that are similar to actual devices. Therefore, in this paper, we propose a method to effectively detect Android emulators for mobile games based on Houdini module and strings of a library. The proposed method detects the two emulators, Nox and LD Player through specific strings included in libc.so of bionic, and an analysis of the system call execution process and memory mapping associated with the Houdini module.

• KIISE Transactions on Computing Practices
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• v.22 no.3
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• pp.139-144
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• 2016

There exist many threats in cyber space, however current anti-virus software and other existing solutions do not effectively respond to malware that has become more complex and sophisticated. It was shown experimentally that it is possible for the proposed approach to provide an automatic execution environment for the detection of malicious behavior of active malware, comparing the virtual-machine environment with the real-machine environment based on user interaction. Moreover, the results show that it is possible to provide a dynamic analysis environment in order to analyze the intelligent malware effectively, through the comparison of malicious behavior activity in an automatic binary execution environment based on real-machines and the malicious behavior activity in a virtual-machine environment.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.283-288
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• 2005

Test case prioritization methods schedule test cases for execution when we can not practically run all test cases for regression testing. We proposed a new prioritization method that is based on historical execution and mr detection data. And we conducted an experiment to compare the proposed method with existing Random and LRU methods using the fault age under the long run environment as criterion. The experiment shows several interesting results. First, our results show that they are complementary. Random method shows good performance for programs that have many error-detectable test cases and HED is more effective for the programs that can be detected by very small amount of test cases. But LRU is more effective for the programs that have relatively medium amount of error detectable test cases. Next, the performance of prioritization method is affected by the size of test suites. Two experiments that have different size of test suites show considerably different fault ages and performance order. And lastly, the $20\%$ of test cases shows considerably good performance compared to the execution result of the full test suite.

• Journal of KIISE
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• v.42 no.2
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• pp.155-161
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• 2015

It is difficult and cumbersome to figure out whether a multithread program runs with concurrency bugs, such as data races and atomicity violations, because there are many possible executions of the program and a lot of the defects are hard to reproduce. Hence, monitoring techniques for collecting and analyzing the information from program execution, such as thread executions, memory accesses, and synchronization information, are important to locate data races for debugging multithread programs. This paper presents an efficient and practical monitoring tool, called VcTrace, that analyzes the partial ordering of concurrent threads and events during an execution of the program based on the vector clock system. Empirical results on C/C++ benchmarks using Pthreads show that VcTrace is a sound and practical tool for on-the-fly data race detection as well as for analyzing multithread programs.