• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.130-132
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• 2002

NATM(Network Abstract Timed Machine)은 통신 네트워크와 같이 다양한 형태의 시스템을 기술하는데 사용되고 크고 복잡한 네트워크에 대해서 요구사항을 만족하도록 설계된 모델링 언어이다. NATM은 기존의 네트워크 설계 언어에서 기술하기 어려운 다양한 형태의 네트워크 표현과 네트워크를 고정 네트워크 환경과 무선 네트워크 환경으로 나누어 유/무선 네트워크 환경을 명세 할 수 있다. 본 논문에서는 NATM의 다양한 네트워크 환경에서의 여러 Component들을 기술하고 이 Component 속성들을 예제를 통해서 살펴본다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.31-33
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• 2002

이동 분산 실시간 시스템(MDRTS:Mobile Distributed Real-Time System)은 특정 시간 내에 분산 네트워크를 통한 정보 교환 및 요구된 동작을 실행한다. 그리고 경로, 시간 및 속력에 관한 제약사항에 따라 머신이 이동하는 시스템이다. 본 논문은 MDRTS에서 발생되는 머신의 이동을 분석하기 위해, PATM[1]에 위치 공간 개념을 추가하여 확장한 DATM(Distributed Abstract Timed Machine)을 정의한다. 머신의 이동과 이동을 제약하는 사항들, 경로, 시간 및 속력 등을 나타내는 표현법을 정의하며, 각 제약 사항에 따른 이동에 관한 규칙을 기술한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.424-426
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• 2002

PATM(Probabilistic Abstract Timed Machine) [1]은 시스템의 진행 중 다양한 환경 요인에 의해 발생하는 불확실성을 명세하기 위해 개발된 정형 명세 기법이다. PATM으로 명세한 시스템은 도달성 그래프를 분석하게 된다. 본 논문에서는 다양한 물리적 환경 요소를 고려하여 시스템을 분석하는 과정에서 발생하는 실행모델의 복잡도를 줄이기 위한 방법을 제시한다.

• Journal of the Korea Society for Simulation
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• v.9 no.1
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• pp.39-54
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• 2000

Presented in this paper is a modeling and simulation methodology for 3 dimensional man-made systems. Based on DEVS(discrete event system specification) formalism[13], we propose GK-DEVS (geometrical and kinematic DEVS) formalism to describe the geometrical and kinematic structure and continuous state dynamics. To represent geometry and kinematics, we add a hierarchical structure to the conventional atomic model. In addition, we employ the "empty event" and its external event function for continuous state changing. In terms of abstract simulation algorithm[13], the simulation method of GK-DEVS, named GK-Simulator, is proposed for combined discrete-continuous simulation. Using GK-DEVS, the simulation of an FMS(flexible manufacturing system) consisting of a luring machine, a 3-axis machine and a RGV-mounted robot has been peformed.en peformed.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.519-522
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• 2004

자바는 현재 가장 널리 사용되는 범용 프로그래밍 언어중 하나로 컴파일러에 의해 중간언어인 바이트코드로 변환되며 JVM(Java Virtual Machine)에 의해 실행되는 플랫폼 독립적인 언어이다. SIL(Standard Intermediate Language)은 Microsoft사의 .NET 언어와 SUN사의 Java 언어 등을 모두 수용할 수 있는 임베디드 시스템을 위한 중간언어로 가상기계인 EVM(Embedded Virtual Machine)에서 실행된다. 본 논문에서는 자바 프로그램을 컴파일하여 생성된 클래스 파일에서 Oolong 코드를 추출하고 추출된 Oolong 코드를 EVM의 SIL 코드로 변환하여 자바로 구현된 프로그램이 EVM에서 실행되도록 하는 Bytecode-to-SIL 번역기 시스템을 구현하였다. 그리고 본 번역기 시스템을 다른 플랫폼에 용이하게 설치하기 위한 재목적성(retargetability)을 위해 단일패스(one-pass)을 사용하는 기존의 번역기들과 달리 AST를 이용한 컴파일러 기법을 사용하여 AST가 가지고 있는 정보에 대해 최적화 작업을 수행하여 보다 효과적인 코드 변환을 할 수 있도록 설계하였다.

• ETRI Journal
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• v.43 no.3
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• pp.549-560
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• 2021

Cyberattacks are often difficult to identify with traditional signature-based detection, because attackers continually find ways to bypass the detection methods. Therefore, researchers have introduced artificial intelligence (AI) technology for cybersecurity analysis to detect malicious PowerShell scripts. In this paper, we propose a feature optimization technique for AI-based approaches to enhance the accuracy of malicious PowerShell script detection. We statically analyze the PowerShell script and preprocess it with a method based on the tokens and abstract syntax tree (AST) for feature selection. Here, tokens and AST represent the vocabulary and structure of the PowerShell script, respectively. Performance evaluations with optimized features yield detection rates of 98% in both machine learning (ML) and deep learning (DL) experiments. Among them, the ML model with the 3-gram of selected five tokens and the DL model with experiments based on the AST 3-gram deliver the best performance.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.153-164
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• 2021

The increasing importance of such fields as embedded systems, pervasive computing, and hybrid systems control is increasing attention to the time-dependent aspects of system modeling. In this paper, we focus on modeling conceptual time. Conceptual time is time represented in conceptual modeling, where the notion of time does not always play a major role. Time modeling in computing is far from exhibiting a unified and comprehensive framework, and is often handled in an ad hoc manner. This paper contributes to the establishment of a broader understanding of time in conceptual modeling based on a software and system engineering model denoted thinging machine (TM). TM modeling is founded on a one-category ontology called a thimac (thing/machine) that is used to elaborate the design and analysis of ontological presumptions. The issue under study is a sample of abstract modeling domains as exemplified by time. The goal is to provide better understanding of the TM model by supplementing it with a conceptualization of time aspects. The results reveal new characteristics of time and related notions such as space, events, and system behavior.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5B
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• pp.286-294
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• 2007

In ASIP design, compiler is required for performance evaluation of processors being designed. The design of machine specific compiler is time consuming. This paper presents the system which generates C compiler from MDL descriptions. Compiler generation using MDL can support user retargetability and concurrency between compiler design and processor design. However, it must overcome semantics gap between compiler and machine. To handle this problem, the proposed system maps behavioral descriptions to library which contains abstract behavior for each tree pattern. Using mapped instructions and information on register file usage, the proposed system generates back-end interface function of the compiler. Generated compilers, for MIPS R3000, ARM9 cores, have been proved by application programs written in C code.

• The Journal of Society for e-Business Studies
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• v.11 no.2
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• pp.93-110
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• 2006

A Business Process Management System(BPMS) requires transaction management to guarantee reliability for transactions. Though several transaction protocols have been suggested for the transaction management, the difference of transaction protocols interrupts interoperability among transaction management systems. In this paper, a business process transaction based on semantics is suggested. It is defined based on the static semantics and the operational semantics. As the static semantics defines the ontologies for transaction states and transaction messages using Web Ontology Language(OWL), it solves the difference of expression for the concepts of transaction protocols. As the operational semantics defines state transitions of business process transactions using Abstract State Machine(ASM), it can guarantee formalism for transaction operations. The operational semantics refers to the state ontology and message ontology defined in the static semantics. This approach can enhance interoperability among various transaction protocols, increase the understandability for the transaction protocols, and support autonomous transaction execution and systematic transaction monitoring.

• Journal of KIISE:Software and Applications
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• v.29 no.12
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• pp.926-939
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• 2002

The formal specification methods with probability have been demanded in the area of fault real-time systems, in order to specify the uncertainty that the systems can encounter during their execution due to various environmental factors. This paper presents a new formal method with probability. namely Probabilistic Abstract Timed Machine (PATM), in order to analyze and predict system's behavior in dynamical environmental changes, This method classifies the factors into two classes: the variable and the constant. The analysis of system's behavior is performed on the probabilistic reachability graph generated from the ATM specification for the system. The analysis can predict any possibility that the behavior may not satisfy some safety requirements of the system, indicate which variable factors cause such satisfaction, and further recover from this unsatisfying fault state by fixing the variable factors. Consequently the reliability to the fault real-time systems can be improved.