• The Journal of Korean Association of Computer Education
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• v.23 no.4
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• pp.35-47
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• 2020

The purpose of this study is to provide a guideline for the programming beginners, including SW non-majors, to reduce the difficulty of establishing procedures for solving problems and to refine the work process properly in a computing environment. To accomplish this, we derive the unfolding types of typical procedures that can unfold the working procedures typically implied in daily operation in terms of recognition(input)-judgment(processing)-behavior(output). Through learning to unfold the procedure for each type, it was confirmed that the learner define the scope and rules of the problem himself and extended the procedure implied in any action. The unfolding model of the procedure developed in this study can be used as a tool for constructing a procedure operable in a computing environment to solve problems in the early stages of programming learning for non-majors or beginners.

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.270-271
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• 2011

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.599-607
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• 2000

This paper suggests an efficient reachability analysis method of bounded petri nets. Reachability analysis is a fundamental basis for studying the dynamic properties of any discrete event systems. However, it takes at least exponential execution time and memory space to verify in general petri nets. That is, state space explosion problem may occur. In this paper, we attack problems of previous approaches - state space explosion and restrictions to applicable petri net classes - by formulating the reachability problem as set operation over structural relations among places on an unfolding.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.4
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• pp.41-49
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• 2010

This paper proposes a new high speed SHA-1 architecture using multiple unfolding and pre-computation techniques. We unfolds iterative hash operations to 2 continuos hash stage and reschedules computation timing. Then, the part of critical path is computed at the previous hash operation round and the rest is performed in the present round. These techniques reduce 3 additions to 2 additions on the critical path. It makes the maximum clock frequency of 118 MHz which provides throughput rate of 5.9 Gbps. The proposed architecture shows 26% higher throughput with a 32% smaller hardware size compared to other counterparts. This paper also introduces a analytical model of multiple SHA-1 architecture at the system level that maps a large input data on SHA-1 block in parallel. The model gives us the required number of SHA-1 blocks for a large multimedia data processing that it helps to make decision hardware configuration. The hs fospeed SHA-1 is useful to generate a condensed message and may strengthen the security of mobile communication and internet service.

• Convergence Security Journal
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• v.16 no.7
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• pp.113-120
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• 2016

This paper presents a new high-speed SHA-1 pipeline architecture having a computation delay close to the maximum critical path delay of the original SHA-1. The typical SHA-1 pipelines are based on either a hash operation or unfolded hash operations. Their throughputs are greatly enhanced by the parallel processing in the pipeline, but the maximum critical path delay will be increased in comparison with the unfolding of all hash operations in each round. The pipeline stage logics in the proposed SHA-1 has the latency is similar with the result of dividing the maximum threshold delay of a round by the number of iterations. Experimental results show that the proposed SHA-1 pipeline structure is 0.99 and 1.62 at the operating speed ratio according to circuit size, which is superior to the conventional structure. The proposed pipeline architecture is expected to be applicable to various cryptographic and signal processing circuits with iterative operations.

• Journal of Radiation Protection and Research
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• v.38 no.3
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• pp.143-148
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• 2013

Operational nuclear facilities such as nuclear power plants and particle accelerators show various neutron spectra according to the type of facilities and specific position. Necessities of neutron dose management and neutron monitoring for radiation protection of radiation workers in such a kind of facilities have continuously increased in recent years. Bonner sphere spectrometers are widely used for measurement of neutron spectra. Data on response function of neutron detector, default neutron spectra and count rates of Bonner sphere spectrometer are required to obtain unfolded neutron spectra in specific workplaces. In this study, we carried out measurement of neutron spectra produced in MC50 cyclotron using Bonner sphere spectrometer with LiI scintillation detector. Additionally, we estimated quantitative data on neutron flux, mean neutron energy and ambient dose equivalent rate according to the incident proton energies and positions in MC50 cyclotron.