• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4924-4931
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• 2011

This research performed to evaluate a production processes reporting by the HACCP system of green vegetable juice products, containing lactic acid bacteria, stage of processing raw materials agricultural products and production facilities of general bacteria and pathogenic micro organism. General bacteria are found from four samples of storage of agricultural products at process stage and water was detected 8.67~14.67 CFU/ml. However, all samples were detected less than 105 CFU/ml as a legal standards after the process of UV sterilization. For the outcome of experiment of E.coli, E.coli O157:H7, B.cereus, L.moonocytogenes, Salmonella spp, Staph.aureus as the food poisoning bacterial, E.coli was detected until UV pre-step process in storage process and B.cereus was detected partly till 1st washing. Since all bacterial, Yeast and Mold are detected in main materials, pre-control method is a necessary to establish for decreasing with a number of initial bacteria of main materials and it is considered to establish the effective ways of washing and sterilization such as production facilities for cross contamination prevention of bacteria and Sthaphylococcus. Based on above results, the process of UV sterilization should be managed with CCP as an important process to reduce or eliminate the general and food poisoning bacterial of green vegetable juice products, including lactic acid bacteria. Therefore, it is considered to need an exhaustive HACCP plan such as control manual of UV sterilization, solution method, verification, education and training and record management.

• Journal of The Korean Association of Information Education
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• v.25 no.3
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• pp.459-469
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• 2021

In this paper, a case study of basic data science practice education for field teachers and pre-service teachers was studied. In this paper, for basic data science education, spreadsheet software was used as a data collection and analysis tool. After that, we trained on statistics for data processing, predictive hypothesis, and predictive model verification. In addition, an educational case for collecting and processing thousands of public big data and verifying the population prediction hypothesis and prediction model was proposed. A 34-hour, 17-week curriculum using a spreadsheet tool was presented with the contents of such basic education in data science. As a tool for data collection, processing, and analysis, unlike Python, spreadsheets do not have the burden of learning program- ming languages and data structures, and have the advantage of visually learning theories of processing and anal- ysis of qualitative and quantitative data. As a result of this educational case study, three predictive hypothesis test cases were presented and analyzed. First, quantitative public data were collected to verify the hypothesis of predicting the difference in the mean value for each group of the population. Second, by collecting qualitative public data, the hypothesis of predicting the association within the qualitative data of the population was verified. Third, by collecting quantitative public data, the regression prediction model was verified according to the hypothesis of correlation prediction within the quantitative data of the population. And through the satisfaction analysis of pre-service and field teachers, the effectiveness of this education case in data science education was analyzed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.167-182
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• 2022

The accident data attributes of the traffic accident report are used not only in traditional traffic safety-related research to identify the cause of traffic accidents, but also as basis data for the development of the automated vehicle driving performance verification scenarios. However, since the data attributes of the traffic accident report are limited for the purpose of reconstructing the traffic situation and developing scenarios, this study aims to provide the directions for improvement of traffic accident report, ultimately for its expanded usability for the automated vehicle test scenarios. The directions for improvement of the traffic accident report are provided by categorizing the traffic situation before the accident (pre-crash), the situation immediately before or during the accident (on-crash), and the situation after the accident (post-crash), respectively. Additional data items or data processing methods are presented. Furthermore, data elements that can be extracted from the traffic accident process data in the unstructured narrative form are explored and provided.

• Journal of The Korean Association of Information Education
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• v.26 no.3
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• pp.197-207
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• 2022

In this paper, we develop a machine learning based block code generation and recommendation model for the purpose of reducing cognitive load of learners during coding education that learns the learner's block that has been made in the block programming environment using natural processing model and fine-tuning and then generates and recommends the selectable blocks for the next step. To develop the model, the training dataset was produced by pre-processing 50 block codes that were on the popular block programming language web site 'Entry'. Also, after dividing the pre-processed blocks into training dataset, verification dataset and test dataset, we developed a model that generates block codes based on LSTM, Seq2Seq, and GPT-2 model. In the results of the performance evaluation of the developed model, GPT-2 showed a higher performance than the LSTM and Seq2Seq model in the BLEU and ROUGE scores which measure sentence similarity. The data results generated through the GPT-2 model, show that the performance was relatively similar in the BLEU and ROUGE scores except for the case where the number of blocks was 1 or 17.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.5
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• pp.567-573
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• 2010

In this study, we evaluated the structural integrity and weight of a rocket motor with a torispherical dome by size optimization. Size optimization was achieved by first-order and sub-problem methods, using the Ansys Parametric Design Language (APDL). For rapid design verification, a modified 2D axisymmetric finite-element model was used, and the bolt pre-tension load was expressed as function of the ratio of the cross-sectional area. The thickness of the dome and the cylindrical part of the rocket motor were selected as the design parameters. Our results showed that the weight and structural integrity of the rocket motor at the initial design stage could be determined more rapidly and accurately with the modified 2D axisymmetric finite-element model than with the 3D finite-element model; further, the weight of the rocket motor could be saved to maximum of 17.6% within safety limit.

• Steel and Composite Structures
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• v.18 no.1
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• pp.255-271
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• 2015

This paper presents the natural frequency of a composite girder with corrugated steel web (CGCSW). A corrugated steel web has negligible in-plane axial stiffness, due to the unique characteristic of corrugated steel webs, which is called the accordion effect. Thus, the corrugated steel web only resists shear force. Further, the shear buckling resistance and out-of-plane stiffness of the web can be enhanced by using a corrugated steel web, since the inclined panels serve as transverse stiffeners. To take these advantages, the corrugated steel web has been used as an alternative to the conventional pre-stressed concrete girder. However, studies about the dynamic characteristics, such as the natural frequency of a CGCSW, have not been sufficiently reported, and it is expected that the natural frequency of a CGCSW is different from that of a composite girder with flat web due to the unique characteristic of the corrugated steel web. In this study, the natural frequency of a CGCSW was investigated through a series of experimental studies and finite element analysis. An experimental study was conducted to evaluate the natural frequency of CGCSW, and the results were compared with those from finite element analysis for verification purpose. A parametric study was then performed to investigate the effect of the geometric characteristics of the corrugated steel web on the natural frequency of the CGCSW. Finally, a simplified beam model to predict the natural frequency of a CGCSW was suggested.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.3
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• pp.339-346
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• 2012

The pre-evaluation of the current-collection performance is an important issue for high-speed railway vehicles. In this paper, using flexible multibody dynamic analysis techniques, a simulation model of the dynamic interaction between the catenary and pantograph is developed. In the analysis model, the pantograph is modeled as a rigid body, and the catenary wire is developed using the absolute nodal coordinate formulation, which can analyze large deformable parts effectively. Moreover, for the representation of the dynamic interaction between these parts, their relative motions are constrained by a sliding joint. Using this analysis model, the contact force and loss of contact can be calculated for a given vehicle speed. The results are evaluated by EN 50318, which is the international standard with regard to analysis model validation. This analysis model may contribute to the evaluation of high-speed railway vehicles that are under development.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.47-52
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• 2018

In this study, a collimator composed of multi-dielectric structures is designed using the phase field design method, a kind of topology optimization methods. It is also purposed to improve the mechanical-structural performance of a collimator by replacing previously used air regions with another dielectric material. Polypropylene and paraffin are selected as the dielectric materials for the design process taking manufacturability into account. The design objective is formulated by integrating the intensity of the electromagnetic field in the pre-determined target area to realize the collimating performance. The model for accurate numerical analysis was derived from the final result obtained from the design process through the simple cut-off method and it shows the improved performance of 105% compared with the free space wave propagation. For the designed model, the possibility of reverse transformation, the mechanical durability evaluation under the compression load, and the electromagnetic performance in the X-band range were also evaluated.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.3
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• pp.61-69
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• 2007

This paper proposes new preprocessing algorithm to extract minutiae in the process of fingerprint recognition. Fingerprint images quality enhancement is a topic phase to ensure good performance in a topic phase to ensure good performance in a Automatic Fingerprint Identification System(AFIS) based on minutiae matching. This paper proposes an algorithm to improve fingerprint image preprocessing to extract minutiae accurately based on directional filter. We improved the suitability of low quality fingerprint images to better suit fingerprint recognition by using valid ridge vector and ridge probability of fingerprint images. With the proposed fingerprint improvement algorithm, noise is removed and presumed ridges are more clearly ascertained. The algorithm is based on five step: computation of effective ridge vector, computation of ridge probability, noise reduction, ridge emphasis, and orientation compensation and frequency estimation. The performance of the proposed approach has been evaluated on two set of images: the first one is self collected using a capacitive semiconductor sensor and second one is DB3 database from Fingerprint Verification Competition (FVC).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.5
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• pp.1175-1186
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• 2015

Financial fraud has been increasing along with credit card usage. Magnetic stripe cards have vulnerabilities in that credit card information is exposed in plaintext and cardholder verification is untrustworthy. So they have been replaced by a smart card scheme to provide enhanced security. Furthermore, the FinTech that combines the IT with Financial product is being prevalent. For that reason, many mobile device based payment schemes have been proposed for card present transaction. In this paper, we propose a virtual credit card number payment scheme based on public key system for efficient authentication in card present transaction. Our proposed scheme is able to authenticate efficiently in card present transaction by pre-registering virtual credit card number based on cardholder's public key without PKI. And we compare and analyze our proposed scheme with EMV.