• Journal of Aerospace System Engineering
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• v.4 no.1
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• pp.23-26
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• 2010

In this study, it was performed damage assesment of small scale composite aircraft developing. This aircraft adopted the sandwich structure to skin of wing. This study aims to investigate the residual strength of sandwich composites with Nomex honeycomb core and carbon fiber face sheets after the open hole damage by the experimental investigation. The 4-point bending tests were used to find the bending strength, and the open hole was applied to introduce the simulated damage on the specimen. The bending strength test results after open hole was compared with the results of no damaged specimen test. The FEM analysis is assessed via an experimental 4-point bending test.

• Journal of Environmental Health Sciences
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• v.46 no.6
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• pp.764-764
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• 2020

• Bulletin of the Korean Mathematical Society
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• v.51 no.4
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• pp.1015-1022
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• 2014

This paper continues the investigation of covers of cyclic acts over monoids. Special attention is paid to (P)-covers and strongly flat covers of cyclic acts. In 2008 Mahmoudi and Renshaw posed some open problems and we gave some examples on them in 2012. In this paper, we obtained some further results on these problems and hence gave some deeper answers to them.

• Journal of The Korean Association For Science Education
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• v.21 no.3
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• pp.506-515
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• 2001

Understanding the students' ability and tendency of self assessment is one of the important factors in helping their learning and in giving the appropriate feedbacks. The purposes of this study is to analyse the coincidency of the students' self-assessment with the teacher assessment, and the tendency of over and under estimation. The students performed open investigations and assessed their process skills by checking their investigation reports with a given checklist. The total mean of the 'Self-Assessment Capability(SAC)' was 0.73 by 1. The SAC was related to the achievement, not to the gender. The correlation between SAC and achievement was significantly positive(r=0.7, p<.01), and for the girls, the tendency was remarkable. Among the five areas of process skills of open investigation, students got the highest SAC score in the managing and interpreting data area, and the lowest SAC in the drawing conclusion area. The mean of 'Self-Assessment Tendency(SAT)' for all items showed that students overestimated their process skills. While the high achievement students underestimated their process skills, the middle and low showed the tendency of overestimation.

• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1195-1207
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• 2020

With the development of GeoWeb technology, 2D/3D spatial information services through the web are also has been used increasingly in the application of disaster management. This paper is suggested to construct a web-based 3D geo-spatial information mapping platform to visualize various spatial information collected at the disaster site in a web environment. This paper is presented a web-based geo-spatial information mapping service plan for the various types of 2D/3D spatial data and large-volume LiDAR point cloud data collected at the disaster accident site using HTML5/WebGL, web development standard technology and open source. Firstly, the collected disaster site survey 2D data is constructed as a spatial DB using GeoServer's WMS service and PostGIS provided an open source and rendered in a web environment. Secondly, in order to efficiently render large-capacity 3D point cloud data in a web environment, a Potree algorithm is applied to simplifies point cloud data into 2D tiles using a multi-resolution octree structure. Lastly, OpenLayers3 based 3D web mapping pilot system is developed for web visualization of 2D/3D spatial information by implementing basic and application functions for controlling and measuring 3D maps with Graphic User Interface (GUI). For the further research, it is expected that various 2D survey data and various spatial image information of a disaster site can be used for scientific investigation and analysis of disaster accidents by overlaying and visualizing them on a built web-based 3D geo-spatial information system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.9
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• pp.2692-2716
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• 2024

Over the past decade, law enforcement organizations have been dealing with the development of cybercrime. To address this growing problem, law enforcement organizations apply various digital forensic (DF) tools and techniques to investigate crimes involving digital devices. This ensures that evidence is admissible in legal proceedings. Consequently, DF analysts may need to invest more in proprietary DF hardware and software to maintain the viability of the DF lab, which will burden budget-constrained organizations. As an alternative, the open source DF tool is considered a cost-saving option. However, the admissibility of digital evidence obtained from these tools has yet to be tested in courts, especially in Malaysia. Therefore, this study aimed to explore the admissibility of digital evidence obtained through open source DF tools. By reviewing the existing literature, the factors that affect the admissibility of the evidence produced by these tools in courts were identified. Further, based on the findings, a conceptual framework was developed to ensure the admissibility of the evidence so that it will be accepted in the court of law. This conceptual framework was formed to outline the factors affecting the admissibility of digital evidence from open source DF tools, which include; 1) The Availability and Capability of open source DF tools, 2) the Reliability and Integrity of the digital evidence obtained from open source DF tools, 3) the Transparency of the open source DF tools, and 4) the Lack of Reference and Standard of open source DF tools. This study provides valuable insights into the digital forensic field, and the conceptual framework can be used to integrate open source DF tools into digital forensic investigations.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.129-134
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• 2003

The importance of understanding the response of structural composites to impact and CAI cannot be overstated to develop analytical models for impact damage and CAI strength predictions. This paper presents experimental findings observed from quasi-static lateral load tests, low velocity impact tests, CAI strength and open hole compressive strength tests using 3mm thick composite plates ($[45/-45/0/90]_{3s}$ - IM7/8552). The conclusion is drawn that damage areas for both quasi-static lateral load and impact tests are similar and the curves of several drop weight impacts with varying energy levels (between 5.4 J and 18.7 J) fallow the static curve well. In addition, at a given energy the peak force is in good agreement between the static and impact cases. From the CAI strength and open hole compressive strength tests, it is identified that the failure behaviour of the specimens was very similar to that observed in laminated plates with open holes under compression loading. The residual strengths are in good agreement with the measured open hole compressive strengths, considering the impact damage site as an equivalent hole. The experimental findings suggest that simple analytical models for the prediction of impact damage area and CAI strength can be developed on the basis of the failure mechanism observed from the experimental tests.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.1
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• pp.45-55
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• 2015

The purpose of this study was to compare the science philosophical views and instruction strategies for open-inquiry between teachers of science-gifted and teachers of general students. The subjects were 45 teachers of science-gifted and 45 teachers of general students. The major results of this study were as follows: First, there was no differences on the science philosophical views between teachers of science-gifted and teachers of general students by chi-square tests (p<.05). Second, there were no differences on how task assignments, how to guide exploration data, and how to write reports between teachers of science-gifted and teachers of general students (p<.05). But there was meaningful differences on how to proceed with exploration activities between teachers of science-gifted and teachers of general students (p<.05). It is implied that this the results of this investigation will help the focus of future efforts to promote more adequate the science philosophical views and instruction strategies for open-inquiry in teachers of science-gifted.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1851-1859
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• 2022

Experimental research on flow characteristics of open natural circulation system was performed, to figure out the mechanism of the open natural circulation behaviors. The influence factors, such as the heating power, the inlet subcooled and the level of cooling tank on the flow characteristics of the system were examined. It was shown that within the scope of the experimental conditions, there are five flow types: single-phase stable flow, flash and geyser coexisting unstable flow, flash stable flow, flash unstable flow, and flash and boiling coexisting unstable flow. The geyser flow in flash and geyser coexisting unstable flow is different from classic geysers flow. The flow oscillation period and amplitude of the former are more regular, is a newly discovered flow pattern. By drawing the flow instability boundary diagram and sorting out the flow types, it is found that the two-phase unstable flow is mainly characterized by boiling and flash, which determine the behavior of open natural circulation respectively or jointly. Moreover, compared with full liquid level system, non-full liquid level system is more prone to boiling phenomenon, and the range of heat flux density and undercooling degree corresponding to unstable flow is larger.

• Journal of The Korean Association For Science Education
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• v.31 no.8
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• pp.1199-1213
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• 2011

The purpose of this study was to investigate the difficulties in engaging in open-inquiry activities - especially finding inquiry topics for student themselves. Data were collected from in-depth interviews with 11 middle school students and their open-inquiry worksheets from 4 months of activities. The investigation tools were composed of three domains for topic choice: selecting subjects, making 10 questions, and choosing a topic with the 10 questions. The study revealed that middle school students have difficulties in the domain of 'object selection' and 'finding inquiry topic.' Under the object selection domain, they showed burden of selection of unlimited subject, lack of knowledge on the science object, and lack of interest in object. Under the domain of finding inquiry topic, they have difficulties from their selected topics that were non-scientific, focus only on interest, lack of background information or those that could be resolved by short answers. Each student has difficulty in doing open-inquiry with relatively different seriousness. The findings suggested that an open inquiry program should be provided along with a systematic guide program on finding inquiry topic for open-inquiry activities to be a successful and continual performance gauge.