가상현실 모델링 언어에 관한 연구

장천현 건국대학교 산업기술연구원 1996 건국기술연구논문지 Vol.21 No.-

The Virtual Reality Modeling Language, VRML, is fast becoming a standard language for describing virtual worlds networked via the global Internet and hyperlinked with the World Wide Web. But the current version of VRML only allows limited interactive behavior for the creation of virtual worlds, and it is not easy to create VRML documents because of its three-dimensional nature. Recently several authoring tools are announced for creating VRML documents, and next version of VRML are proposed for richer behaviors, including animations, motion physics and real-time multi-user interaction. In this paper, we briefly introduce the VRML system with several authoring tools and discuss the comparison with each others. We also briefly introduce the future version of VRML and discuss the comparison between several proposal, This research results will be the basis for design of new authoring tool and adaptation of next version of VRML.

UKC 2005 참관기

장천현 건국대학교 산업기술연구원 2006 건국기술연구논문지 Vol.31 No.-

자바 언어 구현에 관한 연구

장천현 건국대학교 산업기술연구원 1999 건국기술연구논문지 Vol.24 No.-

The Java programming language is emerging as a software distribution standard, with major vendors committed to porting the Java virtual machine(JVM) to their platforms. These first generation JVM rely on an interpreter, possibly extended with capabilities to cache native code for reduced interpreter overhead, to bridge the gap between the bytecode instruction and the native hardware. The interpreter approach is sufficient for specialized applications such as Internet browsers, where application performance is often limited by network delays rather than processor speed. But it is not sufficient for executing general applications distributed in Java bytecode. In this paper, we propose a native executable translation compiler model which is easily retargeted to various target machine. Our model use Sun's Java front-end(javac), and EM code, code expander and back-ends from ACK(Amsterdam Compiler Kit). Code expander which is a bytecode-to-EMcode translator is easily generated from bytecode-to-EMcode mapping description. EM code generated by the code expander is retargerted to various machine by using ACK back-ends. From our result, various native Java compiler may be developed easily.

소프트웨어 프로토타이핑 환경에 관한 연구:병행 프로그래밍 커널 설계

장천현 建國大學校 附設 産業技術硏究所 1993 논문집 Vol.18 No.-

The objective of the prototyping environment is to aid system developers to evaluate new techniques and design alternatives for concurrent or distributed system. One of the primary reasons of the difficulty in successfully developing and evaluating new techniques for concurrent or distributed system is that it takes a long time and huge effort to actually develop a system before the techniques can be evaluated. To reduce the time and effort in this approach, the prototyping environment has been developed based of flexible message-passing concurrent programming kernel. In this paper, we describe the structure of prototyping environment implemented on virtual machine(VM). This prototyping environment is based on concurrent programming kernel which is the most essential part of this system. This kernel is designed and written in Modula-2, which supports well define interfaces and data abstractions. Therfore it is suffificiently enough to construct prototyping environment.

C++ 컴파일러 및 프로그래밍 환경 개발

장천현(Chang Chun Hyon),오세만(Oh Se Man),유재우(Yoo Chae Woo) 한국정보처리학회 1997 정보처리학회논문지 Vol.4 No.3

in this paper, we proposed and developed a compiler and interactive programming environments for C which is mostly worth of notice among the object-oriented languages. To develop the compiler for C we took front-end/back-end model using EM virtual machine. In developing Front-End, we formalized C grammar with the context sensitive tokens which must be manipulated by lexical scanner and designed a AST class library which is the hierarchy of AST node class and well defined interface among them. In developing Back-End, we proposed model for three major components : code optimizer, code generator and run-time environments. We emphasized the retargetable back-end which can be systematically reconfigured to generate code for a variety of distinct target computers. We also developed tree pattern matching algorithm and implemented target code generator which produce SPARC code. We also proposed the theory and model for constructing interactive programming environments. To represent language features we adopt AST as internal representation and propose incremental analysis algorithm and visual diagram. We also studied unparsing scheme, visual diagram, graphical user interface to generate interactive environments automatically. Results of our research will be very useful for developing a compiler and programming environments, and also can be used in compilers for parallel and distributed environments.

OSI 기본 등급 가상터미널 형식 명세를 위한 프로토콜 머신의 설계

한선영,장천현 건국대학교 산업기술연구원 1994 건국기술연구논문지 Vol.19 No.-

OSI 망에서 표준화된 터미날 프로토콜로 점차 관심분야로 대두되는 가상터미널 기본등급 프로토콜은 원격지 호스트와 통신하거나 원격지의 자원에 접근하기 우해 표준화되어 있다. 가상터미널 기본 등급 서비스는 개방 시스템 상호접속 환경(OSIE)에서 제공하고 있는 몇 개의 응용 지향적인 통신 서비스 중 하나이다. 본 논문에서는 OSI 기본 등급 가상터미널의 LOTOS 형식 명세를 위하여 그 프로토콜 머신을 설계하였다. Resulting from the growing interest in the standardized terminal protocol within OSI network, virtual terminal basic class protocol is standardized communication protocol between remote hosts and local terminals, Virtual terminal basic class services is one of the several application-oriented communication services being provided by protocols operating in the application layer of the Open Systems Interconnection Environment(OSIE). In this paper, we design the OSI Virtual Terminal Protocol machine for its LOTOS formal specification.

A Study on Right Context of LR (0) Item

Chang, Chun Hyon 건국대학교 1986 學術誌 Vol.30 No.2

본 논문에서는 LR Parsing방법에 기반을 둔 Syntax Error Repair에서 핵심이 되는 LR(0) Item의 Right Context (Expected Vocabulary String)를 Closure-graph와 L-graph를 이용하여 효과적으로 구하는 방법이 고찰되고 서로 비교되었다. Error Repairing System에 2개의 방법을 적용시켜 Ada와 Pascal 언어의 LALR(1) Grammar에 대해 실험한 결과 L-graph를 이용한 방법이 Closure-graph를 이용한 방법보다 시간 및 기억장소 모든 면에서 우월함을 입증하였다. (Note) Due to the restricted character set of the device on which this text was printed following conventions are introduced. c stands for set membership ∈ U stands for set union ∪ a stands for Greek letter α b stands for Greek letter β c stands for Greek letter γ e stands for Greek letter ε w stands for Greek letter ω { } stands for empty set φ 〈 〉 stands for inequality ≠

컴파일러 개발에 관한 연구 ( A Study on the Development of Compilers )

최광무,장천현,김도형,여미라,장호욱,정민수,채의근,황성훈 한국통신학회 1988 한국통신학회 학술대회논문집 Vol.1 No.1

The Implementation of Smalltalk-80 Virtual Machine

Han,Sun Young,Chang,Chun-Hyon 건국대학교 부설 산업기술연구소 1985 논문집 Vol.10 No.-

Abstraction과 Inheritance의 개념을 이용하여 인간의 사고와 정보교환 수단을 모델화 하여 프로그램에 적용해 보자는 것이 Object-Oriented프로그램의 개념이다. Smalltalk-80은 Object-Oriented프로그램의 대표적인 시스템으로서 본 논문에서는 Smalltalk-80 시스템의 Virtual Machine의 구현에 관하여 기술하였다. Smalltalk-80 시스템은 Xerox에서 최초로 개발한 대규모 Prgramming Enrironment로서 Smalltalk-80 자신으로 쓰여진 Virual Image라는 부분과 Abstract Machine 형태로 기술되는 Virtual Machine으로 구성되어 있다. 따라서 Target Machine에 Smalltalk-80을 구현하기 위해선 그 기종에 맞는 Virtual Machine을 구현하여야 한다. Virtual Machine은 Storage Manager, Interpreter 및 Primitive Subroutine의 세 부분으로 나눌 수 있으며, 본 논문에서는 각각의 부분을 구현하기 위하여 Xerox에서 제공하는 스펙을 따랐다.

Ada Compiler front end의 설계 및 구현

이승재,장천현 한국정보과학회 1986 한국정보과학회 학술발표논문집 Vol.13 No.2(1)

1979년 Dod에서 발표된 이래로 Ada는 이 언어가 가지는 여러 기능들로 꾸준한 연구의 대상이 되어왔다. 본 논문에서는 Ada compiler의 Front end를 설계하고 이에 필요한 자료구조인 Diana의 구현에 중점을 두었다.