• Composites Research
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• v.36 no.6
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• pp.388-394
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• 2023

In composites manufacturing, increasing resin impregnation is a key way to speed up the manufacturing process and improve product quality. While resin improvement is important, simple fiber surface treatments can also improve resin flowability. In this study, different plasma treatment times were applied to carbon fiber fabrics to improve the impregnation between resin and fiber. Electrical resistivity measurements were used to evaluate the dispersion of resin in the fibers, which changed with plasma treatment. The effect of fiber surface treatment on resin spreadability could be observed in real time. When inserting a carbon fiber tow into the resin, the amount of resin that soaked into the tow was measured to objectively compare resin impregnation. Five minutes of plasma treatment improved the tensile and compressive strength of the composite by more than 50%, while reducing the void content and increasing the fire point impregnation flow rate. Finally, a dynamic flexural fatigue test was conducted using a portion of the composite used as an architectural composite part, and the composite part did not fail after one million cycles of a 3 kN load.

• The Journal of the Acoustical Society of Korea
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• v.28 no.4
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• pp.401-407
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• 2009

In this paper, we propose a novel method for the cross-correlation based double-talk detection (DTD), which employing the Gaussian Mixture Model (GMM) in the frequency domain. The proposed algorithm transforms the cross correlation coefficient used in the time domain into 16 channels in the frequency domain using the discrete fourier transform (DFT). The channels are then selected into seven feature vectors for GMM and we identify three different regions such as far-end, double-talk and near-end speech using the likelihood comparison based on those feature vectors. The presented DTD algorithm detects efficiently the double-talk regions without Voice Activity Detector which has been used in conventional cross correlation based double-talk detection. The performance of the proposed algorithm is evaluated under various conditions and yields better results compared with the conventional schemes. especially, show the robustness against detection errors resulting from the background noises or echo path change which one of the key issues in practical DTD.

• Advances in nano research
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• v.16 no.2
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• pp.111-125
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• 2024

Recently, a lot of research has been done on the analysis of axial vibrations of homogeneous and FG nanotubes (nanorods) with various aspects of vibrations that have been fully mentioned in history. However, there is a lack of investigation of the dynamic internal resonances of FG nanotubes (nanorods) between them. This is one of the essential or substantial characteristics of nonlinear vibration systems that have many applications in various fields of engineering (making actuators, sensors, etc.) and medicine (improving the course of diseases such as cancers, etc.). For this reason, in this study, for the first time, the dynamic internal resonances of FG nanorods in the simultaneous presence of large-amplitude size dependent behaviour, inertial and shear effects are investigated for general state in detail. Such theoretical patterns permit as to carry out various numerical experiments, which is the key point in the expansion of advanced nano-devices in different sciences. This research presents an AFG novel nano resonator model based on the axial vibration of the elastic nanorod system in terms of derivation from large-amplitude size dependent internal modals interactions. The Hamilton's Principle is applied to achieve the basic equations in movement and boundary conditions, and a harmonic deferential quadrature method, and a multiple scale solution technique are employed to determine a semi-analytical solution. The interest of the current solution is seen in its specific procedure that useful for deriving general relationships of internal resonances of FG nanorods. The numerical results predicted by the presented formulation are compared with results already published in the literature to indicate the precision and efficiency of the used theory and method. The influences of gradient index, aspect ratio of FG nanorod, mode number, nonlinear effects, and nonlocal effects variations on the mechanical behavior of FG nanorods are examined and discussed in detail. Also, the inertial and shear traces on the formations of internal resonances of FG nanorods are studied, simultaneously. The obtained valid results of this research can be useful and practical as input data of experimental works and construction of devices related to axial vibrations of FG nanorods.

• Information Systems Review
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• v.21 no.2
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• pp.51-67
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• 2019

This study examines IPO underpricing and its interaction with investor attention as one of key factors that can affect post-IPO performance in the short- and long-run. With higher investor attention measured as Google searches around IPO dates, our empirical results show that IT firms are underpriced more severely than non-IT firms. We also demonstrate that investor attention is positively associated with IPO performance in the short-run for both IT and non-IT firms. However, the impact of investor attention is more sustained for IT firms over a longer time horizon when coupled with a high level of underpricing while its impact is neutralized for non-IT firms. Given the unique attributes such as network effects embedded in the IT industry, our findings suggest that IPO underpricing and its interplay with investor attention for IT firms play an important role in shaping long-run performance and ultimately affecting fundamental value.

• Journal of Platform Technology
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• v.11 no.6
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• pp.89-105
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• 2023

With the development of information technology, most of the information has been converted into digital information, leading to the Big Data era. The demand for search platform has increased to enhance accessibility and usability of information in the databases. Big data search software platforms consist of two main components: (1) an indexing component to generate and store data indices for a fast and efficient data search and (2) a searching component to look up the given data fast. As an amount of data has explosively increased, data indexing performance has become a key performance bottleneck of big data search platforms. Though many companies adopted big data search platforms, relatively little research has been made to improve indexing performance. This research study employs Elasticsearch platform, one of the most famous enterprise big data search platforms, and builds physical clusters of 3 nodes to investigate optimal indexing performance configurations. Our comprehensive experiments and studies demonstrate that the proposed optimal Elasticsearch configuration achieves high indexing performance by an average of 3.13 times.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.459-465
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• 2024

The flight control computer applied to manned/unmanned aircraft is one of the key components directly connected to the control of the aircraft, and is generally designed with a redundant architecture so that essential functions for flight can be maintained even if a failure occurs in a single channel. The operational flight program loaded on these redundant flight control computers should be designed considering a time synchronization between channels, input data selection methods from redundant sensors, and fault detection/isolation methods for channels. In this paper, we propose a redundancy management method applied to triplex compact flight control computers for advanced air vehicle. The proposed redundancy management method includes a synchronization algorithm between triplex channels, an input data voting method from sensors, a bus control right selection method for control command output, and a fault detection/isolation method for channels.

• Journal of the Korean Society of Costume
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• v.30
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• pp.261-274
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• 1996

In the present age dominate by both cer-taingty of 1% and uncertainty of 99% 'Fuzzy thinking' of Bart Kosko that is the way to solve the problems by the scientific way through a worldview of Buddhism or Taoism greatly prevails around the world over 'Lateral greatly prevails around the world over 'Lateral thinking' and the authenticity or the right and-wrong of the uncertainty which is the thinking way to find the answer of the problems of illogical way of Edward de Beno against the western vertical thinking were Concurrently fashion designers over the world also adopt the oriental elements. But there exist differences of thoughts between the orient and the occident. And they have dif-ferent thinking way of aestheticism and references of the value on the beauty. Not only beauty but the view through the mind as intuitional thought in which not only the rec-ognition of sense but also the rationalism and the naturalness play key role. The aesthetic sense in the orient contains both the truth and virtue. 2) The beauty of the mean It's from the thought of neutralization of Confucius. The mean or moderation state which in harmony with ethical virtue and aes-thetic beauty is the ideal and is the ultimate. Therefore the thought of Confucian is the creativity in which the balance and the har-mony is most important. Fashion design is also one of the representation of the mean because the spirit of the designer is harmonized for-mlessly with the object of the model of the fashion design. 2) The beauty of skillfulness It indicates the Taoism of Lao-tzu and Chuangtzu. It takes a super-artistic declar-ation that human can feel and recognize the color of colorlessness the sound of sound-lessness and the taste of tastelessness. The thought of arts affected by Taoism is 'ad-vanced age' called the beauty of skillfulness. The view of arts of lao-tzu takes the beauty of cosmos and the nature as a standard. Es-pecially the beauty of inactivity is recognized by the linkage between the beauty and the ugliness. And these things appear in fashion design as a design element such as humor or exaggeration. 3) The beauty of non-dualism It is thought of Buddhism that all evil passions of worry occur form the opposition in dualism. Finally this thought leads to that everything is consistent and truth is only one from the point of view that virtue and vice has on linkage that is 'no virtues no vices' and 'one with two, two, with one, one is not two' A big tendency like this became the root forma-tion of the thought of the oriental arts. 3. Characteristics of the oriental aesthetic sense on the present fashion design 1) The formation of the fashion design on the oriental elements In the picture-incantation which was a representation of an era when the thought of 'cosmic dual forces' dominated the basic polygons of 'a circle square triangle' means both 'one two three' and 'the negative positive mean' of cosmic elements. From this point of view the was of planner cutting in the Orient is dif-ferent from that of the Occidental which is in three-dimensional. The planner polygon type of the cut-pieces comes to have the meaning of the three-dimension when they consist of a suit that has the combination of each cut-piece. This shows the consistency with the principle of cosmos creation of Taoism that one is two two is three and three is every-thing. 2) The coloring and the symbolic represen-tation of the fashion design on the orien-tal elements The sense on the colors in the Orient from the thought of 'the cosmic dual forces and the five elements' is not the experi-enced from the knowledge but contains the consideration of philosophy Five-primary-color representing compass directions Blue(East) Red(South) Yellow(Center) White (West) and Black (North) is called ' the posi-tive' for this five-primary-color secondary-color which comes from the compound of the primary colors is called 'the negative' The thought of 'the cosmic dual forces and the five elements' is also an theory containing the natural order of the cos-mos and this shows the perceptional differ-ence that they are not conceptual but to be recognized and fell directly. A thought of Buddhism which is 'Colors are colorlessness and Clolorlessness are color's proves that. 3) The pattern and symbolic representation of the fashion design on the oriental elements The pattern as a visual style is a figure of symbolic representation which adopt the mental and physical world of human and are the compo-sition of artistic revelation of the human nature and the religous thought of incantation. Es-pecially the symbolic representation of the oriental thought of Confusion. Buddhism and Taoism There are patterns such as plants aminals the oriental four gods and geometry. From the above it's the time toward the 21'th century when the world is constructing one global area and one historical zone. And the exotic mood of the Orient represented in the fashion which doesn't make the common feeling in general does not cease to develop only to express the visual modeling but also adopts the thought religion and the art which are the root of the Orientail and contains inherent willing of modeling.

• Journal of Intelligence and Information Systems
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• v.23 no.3
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• pp.1-27
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• 2017

It is known that the economic sentiment index and macroeconomic indicators are closely related because economic agent's judgment and forecast of the business conditions affect economic fluctuations. For this reason, consumer sentiment or confidence provides steady fodder for business and is treated as an important piece of economic information. In Korea, private consumption accounts and consumer sentiment index highly relevant for both, which is a very important economic indicator for evaluating and forecasting the domestic economic situation. However, despite offering relevant insights into private consumption and GDP, the traditional approach to measuring the consumer confidence based on the survey has several limits. One possible weakness is that it takes considerable time to research, collect, and aggregate the data. If certain urgent issues arise, timely information will not be announced until the end of each month. In addition, the survey only contains information derived from questionnaire items, which means it can be difficult to catch up to the direct effects of newly arising issues. The survey also faces potential declines in response rates and erroneous responses. Therefore, it is necessary to find a way to complement it. For this purpose, we construct and assess an index designed to measure consumer economic sentiment index using sentiment analysis. Unlike the survey-based measures, our index relies on textual analysis to extract sentiment from economic and financial news articles. In particular, text data such as news articles and SNS are timely and cover a wide range of issues; because such sources can quickly capture the economic impact of specific economic issues, they have great potential as economic indicators. There exist two main approaches to the automatic extraction of sentiment from a text, we apply the lexicon-based approach, using sentiment lexicon dictionaries of words annotated with the semantic orientations. In creating the sentiment lexicon dictionaries, we enter the semantic orientation of individual words manually, though we do not attempt a full linguistic analysis (one that involves analysis of word senses or argument structure); this is the limitation of our research and further work in that direction remains possible. In this study, we generate a time series index of economic sentiment in the news. The construction of the index consists of three broad steps: (1) Collecting a large corpus of economic news articles on the web, (2) Applying lexicon-based methods for sentiment analysis of each article to score the article in terms of sentiment orientation (positive, negative and neutral), and (3) Constructing an economic sentiment index of consumers by aggregating monthly time series for each sentiment word. In line with existing scholarly assessments of the relationship between the consumer confidence index and macroeconomic indicators, any new index should be assessed for its usefulness. We examine the new index's usefulness by comparing other economic indicators to the CSI. To check the usefulness of the newly index based on sentiment analysis, trend and cross - correlation analysis are carried out to analyze the relations and lagged structure. Finally, we analyze the forecasting power using the one step ahead of out of sample prediction. As a result, the news sentiment index correlates strongly with related contemporaneous key indicators in almost all experiments. We also find that news sentiment shocks predict future economic activity in most cases. In almost all experiments, the news sentiment index strongly correlates with related contemporaneous key indicators. Furthermore, in most cases, news sentiment shocks predict future economic activity; in head-to-head comparisons, the news sentiment measures outperform survey-based sentiment index as CSI. Policy makers want to understand consumer or public opinions about existing or proposed policies. Such opinions enable relevant government decision-makers to respond quickly to monitor various web media, SNS, or news articles. Textual data, such as news articles and social networks (Twitter, Facebook and blogs) are generated at high-speeds and cover a wide range of issues; because such sources can quickly capture the economic impact of specific economic issues, they have great potential as economic indicators. Although research using unstructured data in economic analysis is in its early stages, but the utilization of data is expected to greatly increase once its usefulness is confirmed.

• Journal of Legislation Research
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• no.41
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• pp.229-260
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• 2011

European Union (EU) law has been a complex but at the same time fascinating subject of study due to its dynamic evolution. In particular, the Lisbon Treaty which entered into force in December 2009 represents the culmination of a decade of attempts at Treaty reform and harmonisation in diverse sectors. Amongst the EU private law fields, company law harmonisation has been one of the hotly debated issues with regards to the freedom of establishment in the internal market. Due to the significant differences between national provisions on company law, it seemed somewhat difficult to harmonise company law. However, Council Regulation 2157/2001 was legislated in 2001 and now provides the basis for the Statute for a European Company (or Societas Europaea: SE). The Statute is also supplemented by the Council Directive 2001/86 on the involvement of employees. The SE Statute is a legal measure in order to contribute to the internal market, and provides a choice for companies that wish to merge, create a joint subsidiary or convert a subsidiary into an SE. Through this option, the SE became a corporate form which is only available to existing companies incorporated in different Member States in the EU. The important question on the meaning of the SE Statute is whether the distinctive characteristics of the SE make it an attractive option to ensure significant numbers of SE registration. In fact, the outcome that has been made through the SE Statute is an example of regulatory competition. The traditional regulatory competition in the freedom of establishment has been the one between national statutes between Member States. However, this time is not a competition between Member States, which means that the Union has joined the area in competition between legal orders and is now in competition with the systems of company law of the Member States.Key Words : European Union, EU Company Law, Societas Europaea, SE Statute, One-tier System, Two-tier System, Race to the Bottom A quite number of scholars expect that the number of SE will increase significantly. Of course, there is no evidence of regulatory competition that Korea faces currently. However, because of the increasing volume of international trade and expansion of regional economic bloc, it is necessary to consider the example of development of EU company law. Addition to the existing SE Statute, the EU Commission has also proposed a new corporate form, Societas Private Europaea (private limited liable company). All of this development in European company law will help firms make their best choice for company establishment. The Delaware-style development in the EU will foster the race to the bottom, thereby improving the contents of company law. To conclude, the study on the development of European company law becomes important to understand the evolution of company law and harmonisation efforts in the EU.

• Journal of Intelligence and Information Systems
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• v.26 no.2
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• pp.131-145
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• 2020

In line with the trend of industrial innovation, IoT technology utilized in a variety of fields is emerging as a key element in creation of new business models and the provision of user-friendly services through the combination of big data. The accumulated data from devices with the Internet-of-Things (IoT) is being used in many ways to build a convenience-based smart system as it can provide customized intelligent systems through user environment and pattern analysis. Recently, it has been applied to innovation in the public domain and has been using it for smart city and smart transportation, such as solving traffic and crime problems using CCTV. In particular, it is necessary to comprehensively consider the easiness of securing real-time service data and the stability of security when planning underground services or establishing movement amount control information system to enhance citizens' or commuters' convenience in circumstances with the congestion of public transportation such as subways, urban railways, etc. However, previous studies that utilize image data have limitations in reducing the performance of object detection under private issue and abnormal conditions. The IoT device-based sensor data used in this study is free from private issue because it does not require identification for individuals, and can be effectively utilized to build intelligent public services for unspecified people. Especially, sensor data stored by the IoT device need not be identified to an individual, and can be effectively utilized for constructing intelligent public services for many and unspecified people as data free form private issue. We utilize the IoT-based infrared sensor devices for an intelligent pedestrian tracking system in metro service which many people use on a daily basis and temperature data measured by sensors are therein transmitted in real time. The experimental environment for collecting data detected in real time from sensors was established for the equally-spaced midpoints of 4×4 upper parts in the ceiling of subway entrances where the actual movement amount of passengers is high, and it measured the temperature change for objects entering and leaving the detection spots. The measured data have gone through a preprocessing in which the reference values for 16 different areas are set and the difference values between the temperatures in 16 distinct areas and their reference values per unit of time are calculated. This corresponds to the methodology that maximizes movement within the detection area. In addition, the size of the data was increased by 10 times in order to more sensitively reflect the difference in temperature by area. For example, if the temperature data collected from the sensor at a given time were 28.5℃, the data analysis was conducted by changing the value to 285. As above, the data collected from sensors have the characteristics of time series data and image data with 4×4 resolution. Reflecting the characteristics of the measured, preprocessed data, we finally propose a hybrid algorithm that combines CNN in superior performance for image classification and LSTM, especially suitable for analyzing time series data, as referred to CNN-LSTM (Convolutional Neural Network-Long Short Term Memory). In the study, the CNN-LSTM algorithm is used to predict the number of passing persons in one of 4×4 detection areas. We verified the validation of the proposed model by taking performance comparison with other artificial intelligence algorithms such as Multi-Layer Perceptron (MLP), Long Short Term Memory (LSTM) and RNN-LSTM (Recurrent Neural Network-Long Short Term Memory). As a result of the experiment, proposed CNN-LSTM hybrid model compared to MLP, LSTM and RNN-LSTM has the best predictive performance. By utilizing the proposed devices and models, it is expected various metro services will be provided with no illegal issue about the personal information such as real-time monitoring of public transport facilities and emergency situation response services on the basis of congestion. However, the data have been collected by selecting one side of the entrances as the subject of analysis, and the data collected for a short period of time have been applied to the prediction. There exists the limitation that the verification of application in other environments needs to be carried out. In the future, it is expected that more reliability will be provided for the proposed model if experimental data is sufficiently collected in various environments or if learning data is further configured by measuring data in other sensors.