• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.42-45
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• 2012

A network processor (NP) is an application-specific instruction-set processor for fast and efficient packet processing. There are many issues in compiler's code generation and optimization due to NP's hardware constraints and special hardware support. In this paper, we describe in detail how to resolve the issues. Our compiler was developed on LLVM 3.0 and the NP target was our in-house network processor which consists of 32 64-bit RISC processors and supports multi-context with special hardware structures. Our compiler incurs only 9.36% code size overhead over hand-written code while satisfying QoS, and the generated code was tested on a real packet processing hardware, called S20 for code verification and performance evaluation.

• Journal of the Korea Society for Simulation
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• v.5 no.1
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• pp.67-79
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• 1996

This paper proposes an intelligent simulation generator, called INSIMS, for manufacturing systems. The INSIMS provides an interactive dialogue interactive dialogue interface and code generation tools for modeling and code genration of manufacturing systems. The interactive dialogue interface helps non-expert simulation modeler specify manufacturing systems with ease. After completing the model construction processes, the modeling specifications are automatically converted into SLAM II codes by code generation tools. To validate the usefulness of INSIMS and to illustrate the modeling processes, an example system has been presented.

• Journal of Internet Computing and Services
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• v.3 no.3
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• pp.1-9
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• 2002

The various researches are investigated for transforming byte code into objective machine code which can be implemented in the specific processor using classical compiling methods to improve the execution speed of the JAVA language. The code generation techniques using pattern matching can generate more high-quality code than code expansion techniques. We provide, in this research, the standardized pattern describing methods and pattern matching techniques that can be used to generate the register-based inter-language which is for the effective native code generation from byte code. And we designed and realized the inter-code transformer with which we can generate the high-quality register-based inter-code using standardized pattern described formerly.

• Journal of Korea Multimedia Society
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• v.5 no.3
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• pp.342-350
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• 2002

The execution speed is not an important factor for Java programming language when implementing small size application program which is executed on the web browser, but it becomes a serious limitation when the huge-size programs are implemented. To overcome this problem, the various research is conducted for translating the Bytecode into the target code which can be implemented in the specific processor by using classical compiling methods. In this research, we have designed and realized an intermediate code translator for the native code generation system with which we can directly generate i386 code from Bytecode to improve the execution speed of Java application programs. The intermediate code translator generates the register-based intermediate code from *.class files which are the intermediate code of Java.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.327-330
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• 2011

CFD simulation is widely used in various industries, universities and research centers. In Korea most of the researchers use foreign commercial S/W packages especially in industries. But commercial CFD packages have some problems as limit to source code and very high license foe. So from several years ago open source CFD code has been widely spread as an alternative. But in Korea there are a few users of open source code. Insufficiency of performance validation as for accuracy, robustness, convenience and parallel speed-up is important obstacles of open source code. So we tested some validation cases as to incompressible external aerodynamics and internal flaws and now are doing compressible flaws. As the first stage of compressible flow validation, we simulated Korea next generation high speed train(HEMU). It's running condition is 400km/hr and maximum Mach number reaches up to 0.4. With the high speed train we tested accuracy, robustness and parallel performance of open source CFD code OpenFOAM Because there isn't experimental data we compared results with widely used commercial code. When use $1^{st}$ order upwind scheme aerodynamic forces are very similar to commercial code. But using $2^{nd}$ order upwind scheme there was some discrepancy. The reason of the difference is not clear yet. Mesh manipulation, domain decomposition, post-processing and robustness are satisfactory. Paralle lperformance is similar to commercial code.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.45-55
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• 2008

Due to the increasing complexity of embedded system design, automatic code generation of embedded software and hardware-software co-design methodologies are gaining great interest from industries and academia. Such an automatic design methodologies are always demanding a formal system specification languages for defining designer's idea clearly and precisely. In this paper, we propose automatic embedded C code generation from SDL (Specification and Description Language, ITU-T recommended the SDL as a standard system description language) with considering a real-time uC/OS-II operating system. Our automatic embedded C code generator is expected to provide a fast specification, verification and performance evaluation platform for embedded software designs.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.771-776
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• 2010

Since the importance of seismic design is greater, dynamic analysis is more widely using than past. The input motion is one of the most important factors of dynamic analysis. However, in Korea input motions are selected from U.S. and Japan those are captured from large magnitude earthquakes without considering seismic environment or generated in frequency domain. In this research, the methodology for generating input motions those are considered seismic environment and design code is proposed. The seismic environment compatibility is considered by performing deaggregation and the design code compatibility is considered by time-domain artificial time history accelration generation method. The results shows that seismic environment and design code compatible input motions are successfully generated.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.395-402
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• 2005

This paper deals with modeling and computer simulation of a full multibody vehicle model for a driving simulator. The multibody vehicle model is based on the recursive formulation and a corresponding simulation code is generated automatically from AUTOCODE, which is a symbolic computation package developed by the authors using MAPLE. The paper describes a procedure for automatically generating a highly efficient simulation code for the full vehicle model, while incorporating realistically modeled components. The following issues have been accounted for in the procedure, including software design for representing a mechanical system in symbolic form as a set of computer data objects, a multibody formulation for systems with various types of connections between bodies, automatic manipulation of symbolic expressions in the multibody formulation, interface design for allowing users to describe unconventional force-and torque-producing components, and a method for accommodating external computer subroutines that may have already been developed. The effectiveness and efficiency of the proposed method have been demonstrated by the simulation code developed and implemented for driving simulation.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.237-244
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• 2023

A signal generation simulator is an economical and useful solution in Global Navigation Satellite System (GNSS) receiver design and testing. A software-defined radio approach is widely used both in receivers and simulators, and its flexible structure to adopt to new signals is ideally suited to the testing of a receiver and signal processing algorithm in the signal design phase of a new satellite-based navigation system before the deployment of satellites in space. The generation of highly accurate delayed sampled codes is essential for generating signals in the simulator, where its sampling rate should be chosen to satisfy constraints such as Nyquist criteria and integer and non-commensurate properties in order not to cause any distortion of original signals. A high sampling rate increases the accuracy of code delay, but decreases the computational efficiency as well, and vice versa. Therefore, the selected sampling rate should be as low as possible while maintaining a certain level of code delay accuracy. This paper presents the lower limits of the sampling rate for GNSS signal generation simulators. In the simulation, two distinct code generation methods depending on the sampling position are evaluated in terms of accuracy versus computational efficiency to show the lower limit of the sampling rate for several GNSS signals.