• Journal of Advanced Navigation Technology
• /
• v.8 no.1
• /
• pp.10-18
• /
• 2004

As a technique for high-quality multimedia service in down-link, the transmit diversity schemes using a orthogonal space-time block codes were proposed. But if the number of transmit antenna is three or more, it was impossible to obtain full diversity gain because of the decline of spectral efficiency. Accordingly, the quasi-orthogonal space-time block code that not required a additional bandwidth was proposed. But using a space-time block codes, the transmit diversity schemes were verified over quasi-static and frequency non-selective channels. Therefore, in this paper, we analyze the performance of OFDM systems, which a frequency selective channel equalized a frequency non-selective channel, adapting the quasi-orthogonal space-time block code, and compare they to the conventional orthogonal space-time block coded OFDM systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.323-326
• /
• 2018

The purpose of this study is to suggest web accessibility improvement direction through web accessibility evaluation of 16 local government education and training institutions. For this purpose, we evaluated the websites of 14 education and training institutions excluding some websites. The evaluation was conducted through automatic evaluation by Open-WAX and manual evaluation by three experts. As a result of the analysis, although the web accessibility compliance rate improved, problems such as alternate text, skip link, and markup error prevention were found. This study suggests the future direction of research and adherence to web accessibility of local governments.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.9 no.2
• /
• pp.95-100
• /
• 2011

Purpose: Ingestion of puffer fish can be poisonous due to the presence of potent neurotoxins such as tetrodotoxin (TTX) found in its tissues. There are few clinical reports related to TTX. We performed this study to evaluate the clinical characteristics of TTX poisoning. Methods: We conducted a retrospective study of the 41 patients diagnosed with TTX poisoning who visited the Seoul Asan medical center from July 2004 and December 2010. A review of patients' electronic medical records and patient telephone interviews were conducted. Diagnosis of TTX poisoning was confirmed by observing the casual link between puffer fish consumption and the development of typical TTX intoxication symptoms. Results: The mean age of the patients included in the study was 46.6 years. The highest incidence of intoxication was observed in patients in their 50s (10 patients). Seasonal distribution of intoxication events included 10 in spring, 7 in summer, 10 in fall, and 14 in winter. In most cases, symptoms occurred within 1 hour of ingestion. A wide range of symptoms were associated with puffer fish ingestion affecting multiple body systems including neuromuscular (27 patients), gastrointestinal (19 patients), and cardiopulmonary/vascular (19 patients). All patients were treated with symptomatic and supportive therapy and recovered completely, without sequelae, within 48 hours. In three cases, ventilator support was required. Conclusion: TTX poisoning is not seasonally related, and patients admitted to the emergency room were observed with a wide range of symptoms. Where TTX poisoning is diagnosed, supportive therapy should be performed. Early intubation and ventilation is important, especially is cases of respiratory failure.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.27 no.4
• /
• pp.85-104
• /
• 2016

The purpose of this study is to suggest the developmental strategies of information literacy program based on the integrated topics to promote inquiry abilities of middle school students who take part in the free semester system. To that end, the content of the 2015 revised curriculum on a national level was analyzed to develop 6 inquiry themes that incorporate Korean, Social Studies, Music and Art. The instruction and learning guide were consisted of three stages of forming a background knowledge, researching and creating and evaluating the conclusion of the research. The detailed activities for research step were consisted of the four steps of recognition of the problem, information analysis and interpretation, compilation of information and evaluation for each activity. Among the themes "environment" and "appreciation" were applied to a public library and a middle school library as a trial. The trial application saw that students took an interest in programs that subject themes are link with various topics. They were also very satisfied with such programs.

• Journal of Advanced Navigation Technology
• /
• v.22 no.5
• /
• pp.415-419
• /
• 2018

This paper predicts and measures the C/N ratio of a beacon signal transmitted from geostationary orbit satellite KorSat 5A ($113^{\circ}E$) at a ground station located in Kimpo. Based on the ground stations, we compared the rain attenuation of the zone K of ITU-R and the rain attenuation which analyzed the domestic weather information. In ITU-R, the Korean rainfall characteristics are classified into zone K, but forecasting the rainfall intensity and attenuation of three adjacent cities based on the cumulative rainfall data per minute from 2013 to 2017. The calculation of rainfall path and attenuation is based on ITU-R recommendations. The change of the C/N according to the rainfall amount was confirmed through the 2 week satellite beacon signal C/N measurement. The predicted critical C/N was decreased to 12 dB at $A_{0.3}$. During the experiment, it was confirmed that it decreased up to 8 dB according to the concentrated rainfall.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.1
• /
• pp.107-118
• /
• 2002

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design of quasi-axisymmetric cold forging product by cold former working. The approach to the system is based on knowledge-based rules and a process knowledge base consisting of design rules is built. Knowledge for the system is formulated from plasticity theories, empirical results and the empirical knowledge of field experts. Programs for the system have been written in AutoLISP for the AutoCAD using a personal computer. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system is composed of three main modules and five sub-modules. The process planning and die design module considers several factors, such as the complexities of preform geometry, punch and die profiles, specifications of available cold farmer, and the availability of standard parts. As the system using 2D geometry recognition is integrated with the technology of process planning, die design, and CAE analysis, the standardization of die parts for wheel bolt requiring cold forging process is possible. The developed system makes it possible to design and manufacture quasi-axisymmetric cold forging product more efficiently.

• Journal of Korea Game Society
• /
• v.13 no.4
• /
• pp.47-60
• /
• 2013

Current perception of games is divided. On the one hand, they are criticized as harmful entertainment due to their violent content and addictive nature, and on the other hand, they are evaluated positively as products of a creative industry that offers alternative, interactive entertainment. Based on the latter, this paper will reevaluate the positive element of such games in relation to the museum, the canon of historical and cultural evaluation. The analysis on game culture introduction to the museums consists of three categories: the practical application that includes educational, communicational, and promotional purposes; the approval of games as industrial assets and their extensive cultural influence; and the indirect acceptance of art works using games. A panoramic view of game culture development would promote research on the link between game culture and museums; furthermore, it would establish a basis for an introduction of game culture in academia and predict the future of the industry.

• STI Policy Review
• /
• v.8 no.1
• /
• pp.113-156
• /
• 2017

Although technological progress is considered a key element for economic growth and development of a country, strong empirical evidence in this regard is not available yet. Therefore, to establish the empirical link between technology progress and economic development, it is advisable to carry out a time series analysis. In this regard, the Technology Achievement Index (TAI) of 100 top economies has been developed to examine the position of countries' technological progress for the 21 years spanning 1995 to 2015. Countries have been ranked on their TAI which is based on four pillars; technology creation, diffusion of older innovations, diffusion of recent innovations, and development of human skills. As well, this current study re-calculates the Humane Development Index (HDI) of 100 top economies for the 21 years from 1995 to 2015. Ranking of countries' HDI values reflects three dimensions: A long lifespan (life expectancy index), knowledge (Education Index) and a decent standard of living (Gross National Income Index, or GNI). The Standard Deviation (SD) technique has been used to investigate the technological gap between individual countries and groups of countries or regions. For a more meaningful assessment, technological gaps from the maximum achievement value (i.e., one of the countries under study) are presented as well. To investigate the impact of technological progress on economic development, this study introduces a model in which the HDI is used as the dependent variable and the TAI and Gross Capital Formation (GCF) are used as independent variables. The HDI, TAI and GCF are used in this model as proxy variables for economic development, technological progress and capital respectively. Econometric techniques have been used to show the impact of technological progress on economic development. The results show that long-term associations exist between technology progress and economic development; the impact of technology progress on economic development is 13.2% while the impact is 4.3% higher in eight selected East South Asian countries, at 13.5%, than in eight selected highly developed countries (9.2%).

• KIPS Transactions on Software and Data Engineering
• /
• v.3 no.5
• /
• pp.179-186
• /
• 2014

Current networks such as social network, web page link, traffic network are big data which have the large numbers of nodes and edges. Many applications such as social network services and navigation systems use these networks. Since big networks are not fit into the memory, existing in-memory based analysis techniques cannot provide high performance. Frontier-Expansion-Merge (FEM) framework for graph search operations using three corresponding operators in the relational database (RDB) context. FEM exploits an index table that stores pre-computed partial paths for efficient shortest path discovery. However, the index table of FEM has low hit ratio because the indices are determined by distances of indices rather than the possibility of containing a shortest path. In this paper, we propose an method that construct index table using high degree nodes having high hit ratio for efficient shortest path discovery. We experimentally verify that our index technique can support shortest path discovery efficiently in real-world datasets.

• Journal of Elementary Mathematics Education in Korea
• /
• v.15 no.3
• /
• pp.579-598
• /
• 2011

In this study, the 2011 elementary school mathematics curriculum was analyzed compared to the 2007 elementary school mathematics curriculum with a focus on changes in specified learning topics. First, the topics which are dealt with in the 2011 curriculum were critically discussed. Second, prominent features which can be found in learning topics in 2011 curriculum were found. The following three conclusions which can be obtained from above analyzed results were presented. First, system for curriculum development is necessary to supplement. The process of draft development for public hearing and final curriculum development is not exposed anywhere. It is necessary to clean up and disclose this process in order to study and develop next curriculum. Second, it is necessary to modify the way of stating in curriculum. it is necessary to specify and use the expressions to some extent the meaning of which are not sufficiently established and the meaning of which are ambiguous. Third, the achievement standards set by 2011 curriculum needs to be consistent. The principles for stating achievement standards are necessary. it is necessary to review the link between elementary and middle school curriculum is well-made.