• Publications of The Korean Astronomical Society
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• v.24 no.1
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• pp.43-51
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• 2009

We present a Monte-Carlo simulation code, which solves the problem of dust-scattering in interstellar dust clouds with arbitrary light source distribution and dust density structure, and calculate the surface brightness distribution. The method is very flexible and can be applied to radiative transfer problems occurring not only in a single dust cloud, but also in extragalactic dust environment. We compare, for performance test, the result of Monte-Carlo simulation with the well-known analytic approximation for a spherically symmetric homogeneous cloud. We find that the Code approximation gives a very accurate result.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.746-750
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• 2015

In this paper, we propose a simulator to evaluate the performance of the semi-active laser guidance or the quadrant photodetector and to simulate the laser power reflected from a target. The laser pulse repetition frequency was generated and synchronized with the laser pulse repetition(PRF) code. To evaluate the performances of the proposed methods, we implemented a prototype system and performed experiments. As a result, the generated high voltage was variable in the range of DC 3V to 340V and has the rate of change of 2000 V/s. PRF code can be generated within 50ms ∼ 100ms and the error is implemented within 0.3ns. The laser output is synchronized with the PRF code and has a dynamic range of 23.6dB.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1143-1156
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• 2017

This paper describes recent development activities of the GENESIS code, which is a transport code for heterogeneous three-dimensional geometry, focusing on applications to reactor core analysis. For the treatment of anisotropic scattering, the concept of the simplified Pn method is introduced in order to reduce storage of flux moments. The accuracy of the present method is verified through a benchmark problem. Next, the iteration stability of the GENESIS code for the highly voided condition, which would appear in a severe accident (e.g., design extension) conditions, is discussed. The efficiencies of the coarse mesh finite difference and generalized coarse mesh rebalance acceleration methods are verified with various stabilization techniques. Use of the effective diffusion coefficient and the artificial grid diffusion coefficients are found to be effective to stabilize the acceleration calculation in highly voided conditions.

• Journal of Advanced Navigation Technology
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• v.17 no.5
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• pp.545-551
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• 2013

Packed technique makes difficult to respond quickly because the malicious-code is reduced size that easy to diffusion and changed code that make spend longer time for analysis. In this paper, we analysed the packing tool softwares and we proposed construction and detection methods of the packed technique for easy to analysis of the packed malicious code based on variation of entropy value.

• Wind and Structures
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• v.37 no.2
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• pp.117-131
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• 2023

Korea Design Standard (KDS) will be updated with two major revisions on the assessment of wind load and performance-based wind design (PBWD). Major changes on the wind load assessment are the wind load factor and basic wind speed. Wind load factor in KDS is reduced from 1.3 to 1, and mean recurrence interval (MRI) for basic wind speed increases from 100 years to 500 years considering the reduction of wind load factor. Additional modification is made including pressure coefficient, torsional moment coefficient and spectrum, and aeroelastic instability. Combined effect of the updates of KDS code on the assessment of wind load is discussed with the case study on the specified sites and building. PBWD is newly added in KDS code to consider the cases with various target performance, vortex-induced vibration, aeroelastic instability, or inelastic behavior. Proposed methods and target performance for PBWD in KDS code are introduced.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.8
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• pp.868-872
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• 2010

Many embedded Java systems are equipped with limited memory, which can constrain the code cache size provided for Java just-in-time compilation, affecting the Java performance. This paper proposes expanding the limited code cache when it is full, by saving the machine code for some methods in the code cache into the file system of the permanent storage and reloading it to the code cache when they are re-invoked later. This is applying the client ahead-of-time compilation during the execution time for the purpose of enlarging the code cache. Our experimental results indicate that the proposed execution method can improve the performance by as much as 1.6 times compared to the conventional method, when the code cache size is reduced by half.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1054-1061
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• 2015

The International Maritime Organization (IMO) has been regulating emissions by making mandatory the compliance with institutions aimed at protecting air quality such as the Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and Tier III. Under the circumstances, one of the response measures considered to be the most feasible is the replacement of existing marine fuel with Liquefied Natural Gas (LNG). The industry has been preemptively building infrastructure and developing and spreading engine technology to enable the use of LNG-fueled ships. The IMO, in turn, recently adopted the International Code of Safety for Ships Using Gases or Other Low-Flash-Point Fuels (IGF Code) as an institutional measure. Thus, it is required to comply with regulations on safety-related design and systems focused on response against potential risk for LNG-fueled ships, in which low-flash-point fuel is handled in the engine room. Especially, the Standards of Training, Certification and Watchkeeping (STCW) Convention was amended accordingly. It has adopted the qualification and training requirements for seafarers who are to provide service aboard ships subject to the IGF Code exemplified by LNG-fueled ships. The expansion in the use of LNG-fueled ships and relevant facilities in fact is expected to increase demand for talents. Thus, the time is ripe to develop methods to set up appropriate STCW training courses for seafarers who board ships subject to the IGF Code. In this study, the STCW Convention and existing STCW training courses applied to seafarers offering service aboard ships subject to the IGF Code are reviewed. The results were reflected to propose ways to design new STCW training courses needed for ships subject to the IGF Code and to identify and improve insufficiencies of the STCW Convention in relation to the IGF Code.

• Journal of Software Assessment and Valuation
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• v.16 no.1
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• pp.37-44
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• 2020

The similarity of the software is extracted by the verification of comparing with the source code. The source code is the intellectual copyright of the developer written in the programming language. And the source code written in text format contains the contents of the developer's expertise and ideas. The verification for judging the illegal use of software copyright is performed by comparing the structure and contents of files with the source code of the original and the illegal copy. However, there is hard to do the one-to-one comparison in practice. Cause the suspected source code do not submitted Intentionally or unconsciously. It is now increasing practically. In this case, the comparative evaluation with execution code should be performed, and indirect methods such as reverse assembling method, reverse engineering technique, and sequence analysis of function execution are applied. In this paper, we analyzed the effectiveness of indirect comparison results by practical evaluation . It also proposes a method to utilize to the system and executable code files as a verification results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1854-1863
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• 2003

In the recent digital communication systems, the performance of Turbo Code using the mr correction coding depends on the interleaver influencing the free distance determination and the recursive decoding algorithms that is executed in the huh decoder. However, performance depends on the interleaver depth that needs many delays over the reception process. Moreover, turbo code has been blown as the robust coding methods with the confidence over the fading channel. International Telecommunication Union(ITU) has recently adopted it as the standardization of the channel coding over the third generation mobile communications(IMT­2000). Therefore, in this paper, we preposed the interleaver that has the better performance than existing block interleaver, and modified turbo decoder that has the parallel concatenated structure using MAP algorithm. In the real­time voice and video service over third generation mobile communications, the performance of the proposed two methods was analyzed and compared with the existing methods by computer simulation in terms of reduced decoding delay using the variable decoding method over AWGN and fading channels for CDMA environments.

• The Journal of Korean Institute of Information Technology
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• v.16 no.12
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• pp.69-74
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• 2018

The road name address is a two-dimensional location marking method for naming each road and assigning a number to each building. However, the road name address only shows the necessary parts for administrative and legal acts, and it does not properly display the main characteristics of various roads and non-residential areas. This has become more and more difficult to standardize different location identification methods, merely as a separate location identification method. This paper proposes road-based 3D location identification code to overcome the difficulties of integrating different location identification methods in Korea and to overcome the limit of 2D plane. This is a method to integrate various location identification methods based on roads and to identify spatial coordinates. It is a study on 3D digital coding of the land suitable for the 4th Industrial Revolution era.