• Korean Journal of Optics and Photonics
• /
• v.16 no.3
• /
• pp.182-190
• /
• 2005

The fiber Raman amplifier(FRA) is a distinctly advantageous technology. Due to its wider, flexible gain bandwidth, and intrinsically lower noise characteristics, FRA has become an indispensable technology of today. Various FRA modeling methods, with different levels of convergence speed and accuracy, have been proposed in order to gain valuable insights for the FRA dynamics and optimum design before real implementation. Still, all these approaches share the common platform of coupled ordinary differential equations(ODE) for the Raman equation set that must be solved along the long length of fiber propagation axis. The ODE platform has classically set the bar for achievable convergence speed, resulting exhaustive calculation efforts. In this work, we propose an alternative, highly efficient framework for FRA analysis. In treating the Raman gain as the perturbation factor in an adiabatic process, we achieved implementation of the algorithm by deriving a recursive relation for the integrals of power inside fiber with the effective length and by constructing a matrix formalism for the solution of the given FRA problem. Finally, by adiabatically turning on the Raman process in the fiber as increasing the order of iterations, the FRA solution can be obtained along the iteration axis for the whole length of fiber rather than along the fiber propagation axis, enabling faster convergence speed, at the equivalent accuracy achievable with the methods based on coupled ODEs. Performance comparison in all co-, counter-, bi-directionally pumped multi-channel FRA shows more than 102 times faster with the convergence speed of the Average power method at the same level of accuracy(relative deviation < 0.03dB).

• Journal of Intelligence and Information Systems
• /
• v.25 no.4
• /
• pp.67-88
• /
• 2019

Webtoon is a Korean-style digital comics platform that distributes comics content produced using the characteristic elements of the Internet in a form that can be consumed online. With the recent rapid growth of the webtoon industry and the exponential increase in the supply of webtoon content, the need for effective webtoon content recommendation measures is growing. Webtoons are digital content products that combine pictorial, literary and digital elements. Therefore, webtoons stimulate consumer sentiment by making readers have fun and engaging and empathizing with the situations in which webtoons are produced. In this context, it can be expected that the sentiment that webtoons evoke to consumers will serve as an important criterion for consumers' choice of webtoons. However, there is a lack of research to improve webtoons' recommendation performance by utilizing consumer sentiment. This study is aimed at developing consumer sentiment pattern maps that can support effective recommendations of webtoon content, focusing on consumer sentiments that have not been fully discussed previously. Metadata and consumer sentiments data were collected for 200 works serviced on the Korean webtoon platform 'Naver Webtoon' to conduct this study. 488 sentiment terms were collected for 127 works, excluding those that did not meet the purpose of the analysis. Next, similar or duplicate terms were combined or abstracted in accordance with the bottom-up approach. As a result, we have built webtoons specialized sentiment-index, which are reduced to a total of 63 emotive adjectives. By performing exploratory factor analysis on the constructed sentiment-index, we have derived three important dimensions for classifying webtoon types. The exploratory factor analysis was performed through the Principal Component Analysis (PCA) using varimax factor rotation. The three dimensions were named 'Immersion', 'Touch' and 'Irritant' respectively. Based on this, K-Means clustering was performed and the entire webtoons were classified into four types. Each type was named 'Snack', 'Drama', 'Irritant', and 'Romance'. For each type of webtoon, we wrote webtoon-sentiment 2-Mode network graphs and looked at the characteristics of the sentiment pattern appearing for each type. In addition, through profiling analysis, we were able to derive meaningful strategic implications for each type of webtoon. First, The 'Snack' cluster is a collection of webtoons that are fast-paced and highly entertaining. Many consumers are interested in these webtoons, but they don't rate them well. Also, consumers mostly use simple expressions of sentiment when talking about these webtoons. Webtoons belonging to 'Snack' are expected to appeal to modern people who want to consume content easily and quickly during short travel time, such as commuting time. Secondly, webtoons belonging to 'Drama' are expected to evoke realistic and everyday sentiments rather than exaggerated and light comic ones. When consumers talk about webtoons belonging to a 'Drama' cluster in online, they are found to express a variety of sentiments. It is appropriate to establish an OSMU(One source multi-use) strategy to extend these webtoons to other content such as movies and TV series. Third, the sentiment pattern map of 'Irritant' shows the sentiments that discourage customer interest by stimulating discomfort. Webtoons that evoke these sentiments are hard to get public attention. Artists should pay attention to these sentiments that cause inconvenience to consumers in creating webtoons. Finally, Webtoons belonging to 'Romance' do not evoke a variety of consumer sentiments, but they are interpreted as touching consumers. They are expected to be consumed as 'healing content' targeted at consumers with high levels of stress or mental fatigue in their lives. The results of this study are meaningful in that it identifies the applicability of consumer sentiment in the areas of recommendation and classification of webtoons, and provides guidelines to help members of webtoons' ecosystem better understand consumers and formulate strategies.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.6
• /
• pp.467-478
• /
• 2020

Hypervisor virtualize hardware resources to utilize them more effectively. At the same time, hypervisor's characteristics of time and space partitioning improves reliability of flight software by reducing a complexity of the flight software. Korea Aerospace Research Institute chooses one of hypervisors for space, XtratuM, and examine its applicability to the flight software. XtratuM has strong points in performance improvement with high reliability. However, it does not support SMP. Therefore, it has limitation in using it with high performance applications including satellite altitude orbit control systems. This paper proposes RTEMS XM-SMP to support SMP with RTEMS, one of real time operating systems for space. Several components are added as hypercalls, and initialization processes are modified to use several processors with inter processors communication routines. In addition, all components related to processors are updated including context switch and interrupts. The effectiveness of the developed RTEMS XM-SMP is demonstrated with a GR740 board by executing SMP benchmark functions. Performance improvements are reviewed to check the effectiveness of SMP operations.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.4
• /
• pp.284-291
• /
• 2017

There is no doubt that advances in UAV technology have improved military performance. However, these advances require humans to adapt to new and complex operational systems. UAV has been rapidly expanding to a variety of fields such as reconnaissance, transportation, communication and aerial photographing recently. Also, with the development of UAV automation technology, one operator is able to supervisory-control multiple-UAVs. However, as the number of assigned UAV increases, the amount of information increases and this results in the workload of the operator increasing and deterioration in controlling performance. Accordingly, there is a need for a model to determine the level of overload an operator may encounter with regard to multiple-UAV but nationally this kind of research is currently lacking. Therefore, this paper provides an experimental platform for evaluating workload index effectiveness integrating multiple-UAV operational environments, GCS, and eye-tracking system followed by a limited survey of domestic and international studies of multi-UAV overload studies.

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

• Asia pacific journal of information systems
• /
• v.17 no.4
• /
• pp.1-29
• /
• 2007

The brand-based online community recently plays an important roles for consumers to facilitates searching and sharing information among them. Firms often find such a brand community as a critical channel to gain collective intelligence for developing new ideas and products. As a new web platform such as web 2.0 has been introduced, consumers could more easily participate in the new social networks created by sharing mutual value and belief among themselves. Accordingly firms began to recognize potentials of online brand assets and pay attention to the importance of online brand community loyalty. Previous research related to online community tends to focus on identifying the antecedents of community loyalty and their subsequent impacts on brand. They, however, tend to neglect the importance of individual characteristics of online community users. As integrating the fragmented variables with an individual characteristics, therefore, this study reexamined the impacts of interactivity, information, reward, and personalization services provided by an online brand community on the sense of community, community loyalty, and brand attitude. Also, this study investigated how users' individual characteristics(need for cognition: NFC) can play moderating roles among the variables identified in the previous research. A field survey was administrated and 671 valid samples were collected. In order to test the hypothesis we conducted the multi-sample structural equation modeling(MSEM) between two groups(a group with high vs. a group with low level of NFC). Results show that previously identified variables such as interactivity, information, reward, and personalization services have significant effects on the sense of community as previous research demonstrated. Subsequently, the sense of community positively influences the community loyalty and brand attitude. However, when considering the NFC as a moderating variable, we found that the effect of interactivity and reward service on the sense of community was stronger for a group with a lower level of NFC compared to a group with a higher level, while the effect of information providing service on the sense of community was stronger for a group with a higher level of NFC compared to a group with a lower level. This research revealed that NFC can affect the degree of individual perception on the sense of community which has been considered as an important indicator for the community loyalty and brand attitude. Hence, when firms developing customer relation strategy through building an online brand community, they need to reflect customers' NFC and accordingly provide varying degree of interactivity, information, reward, and personalization services.

• Korean Journal of Remote Sensing
• /
• v.36 no.3
• /
• pp.475-486
• /
• 2020

Climate change scenarios are the basis of research to cope with climate change, and consist of large-scale spatio-temporal data. From the data point of view, one scenario has a large capacity of about 83 gigabytes or more, and the data format is semi-structured, making it difficult to utilize the data through means such as search, extraction, archiving and analysis. In this study, a tool for analyzing extreme climate events based on spatial information is developed to improve the usability of large-scale, multi-period climate change scenarios. In addition, a pilot analysis is conducted on the time and space in which the heavy rain thresholds that occurred in the past can occur in the future, by applying the developed tool to the RCP8.5 climate change scenario. As a result, the days with a cumulative rainfall of more than 587.6 mm over three days would account for about 76 days in the 2080s, and localized heavy rains would occur. The developed analysis tool was designed to facilitate the entire process from the initial setting through to deriving analysis results on a single platform, and enabled the results of the analysis to be implemented in various formats without using specific commercial software: web document format (HTML), image (PNG), climate change scenario (ESR), statistics (XLS). Therefore, the utilization of this analysis tool is considered to be useful for determining future prospects for climate change or vulnerability assessment, etc., and it is expected to be used to develop an analysis tool for climate change scenarios based on climate change reports to be presented in the future.

• The Journal of Korean Association of Computer Education
• /
• v.23 no.4
• /
• pp.1-11
• /
• 2020

The purpose of this study is to propose the direction of AI education in K-12 education through investigating and analyzing aspects of the purpose, content, and methods of AI education as the curriculum and teacher training factors. We collected and analyzed 9 papers as the primary literature and 11 domestic and foreign policy reports as the secondary literature. The collected literatures were analyzed by applying a descriptive reviews, and the implications were derived by analyzing the curriculum components and TPACK elements for multi-dimensional analysis. As a result of this study, AI education targets were divided into three steps: AI users, utilizer, and developers. In K-12 education, the user and utilizer stages are appropriate, and artificial intelligence literacy must be included for user education. Based on the current computing thinking ability and coding ability for utilizer education, the implication was derived that it is necessary to target the ability to create creative output by applying the functions of artificial intelligence. In addition to the pedagogical knowledge and the ability to use the platform, The teacher training is necessary because teachers need content knowledge such as problem-solving, reasoning, learning, perception, and some applied mathematics, cognitive / psychological / ethical of AI.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.40.3-41
• /
• 2017

Korea Astronomy and Space Science Institute The observation of particles and waves using a single satellite inherently suffers from space-time ambiguity. Recently, such ambiguity has often been resolved by multi-satellite observations; however, the inter-satellite distances were generally larger than 100 km. Hence, the ambiguity could be resolved only for large-scale (> 100 km) structures while numerous microscale phenomena have been observed at low altitude satellite orbits. In order to resolve those spatial and temporal variations of the microscale plasma structures on the topside ionosphere, SNIPE mission consisted of four (TBD) nanosatellites (~10 kg) will be launched into a polar orbit at an altitude of 700 km (TBD). Two pairs of satellites will be deployed on orbit and the distances between each satellite will be from 10 to 100 km controlled by a formation flying algorithm. The SNIPE mission is equipped with scientific payloads which can measure the following geophysical parameters: density/temperature of cold ionospheric electrons, energetic (~100 keV) electron flux, and magnetic field vectors. All the payloads will have high temporal resolution (~ 16 Hz (TBD)). This mission is planned to launch in 2020. The SNIPE mission aims to elucidate microscale (100 m-10 km) structures in the topside ionosphere (below altitude of 1,000 km), especially the fine-scale morphology of high-energy electron precipitation, cold plasma density/temperature, field-aligned currents, and electromagnetic waves. Hence, the mission will observe microscale structures of the following phenomena in geospace: high-latitude irregularities, such as polar-cap patches; field-aligned currents in the auroral oval; electro-magnetic ion cyclotron (EMIC) waves; hundreds keV electrons' precipitations, such as electron microbursts; subauroral plasma density troughs; and low-latitude plasma irregularities, such as ionospheric blobs and bubbles. We have developed a 6U nanosatellite bus system as the basic platform for the SNIPE mission. Three basic plasma instruments shall be installed on all of each spacecraft, Particle Detector (PD), Langmuir Probe (LP), and Scientific MAGnetometer (SMAG). In addition we now discuss with NASA and JAXA to collaborate with the other payload opportunities into SNIPE mission.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.48 no.1
• /
• pp.116-126
• /
• 2011

In this paper, we present a multi-media processor which can decode multiple-format video standards. The designed processor is evaluated with optimized MPEG-2, MPEG-4, and AVS (Audio video standard). There are two approaches for developing of real-time video decoders. First, hardware-based system is much superior to a processor-based one in execution time. However, it takes long time to implement and modify hardware systems. On the contrary, the software-based video codecs can be easily implemented and flexible, however, their performance is not so good for real-time applications. In this paper, in order to exploit benefits related to two approaches, we designed a processor called ASIP(Application specific instruction-set processor) for video decoding. In our work, we extracted eight common modules from various video decoders, and added several multimedia instructions to the processor. The developed processor for video decoders is evaluated with the Synopsys platform simulator and a FPGA board. In our experiment, we can achieve about 37% time saving in total decoding time.