• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.9
• /
• pp.3357-3376
• /
• 2015

Wireless sensor network is an important research topic that has attracted a lot of attention in recent years. However, most of the interest has focused on wireless sensor network to gather scalar data such as temperature, humidity and vibration. Scalar data are insufficient for diverse applications such as video surveillance, target recognition and traffic monitoring. However, if we use camera sensors in wireless sensor network to collect video data which are vast in information, they can provide important visual information. Video sensor networks continue to gain interest due to their ability to collect video information for a wide range of applications in the past few years. However, how to efficiently store the massive data that reflect environmental state of different times in video sensor network and how to quickly search interested information from them are challenging issues in current research, especially when the sensor network environment is complicated. Therefore, in this paper, we propose a fast algorithm for extracting key frames from video and describe the design and implementation of key frame extraction and sharing in Android for wireless video sensor network.

• Journal of Positioning, Navigation, and Timing
• /
• v.13 no.1
• /
• pp.25-34
• /
• 2024

The Satellite Based Augmentation System (SBAS) improves the accuracy and reliability of user positioning by transmitting the error correction and integrity information of the global navigation satellite system signal from geostationary satellites in real time. For this reason, SBAS was designed for aircraft operations and approach procedures and is now in operational or development stages in many countries. Time has passed since the construction of SBAS and many changes have occurred in the composition of the monitoring stations and the geostationary satellites. These changes have been investigated and the current operation and development status of SBAS globally are surveyed. The development and test schedules for the transition to dual frequency multi-constellation, an important topic in SBAS, are discussed.

• KIISE Transactions on Computing Practices
• /
• v.21 no.12
• /
• pp.768-773
• /
• 2015

Emergence events are the cause of much economic damage. In order to minimize the damage that these events cause, it must be possible to predict what will happen in the future. Accordingly, many researchers have focused on real-time monitoring, detecting events, and investigating events. In addition, there have also been many studies on predictive analysis for forecasting of future trends. However, most studies provide future tendency per event without contextual compositive analysis. In this paper, we present a predictive visual analytics system using topic composition to provide future trends per event. We first extract abnormal topics from social media data to find interesting and unexpected events. We then search for similar emergence patterns in the past. Relevant topics in the past are provided by news media data. Finally, the user combines the relevant topics and a new context is created for contextual prediction. In a case study, we demonstrate our visual analytics system with two different cases and validate our system with possible predictive story lines.

• The Journal of the Korea Contents Association
• /
• v.21 no.4
• /
• pp.1-13
• /
• 2021

With the global pandemic of COVID-19, it is pointed out that exposure to false information to the public could cause serious problems. However, in pandemic situations, there is also an positive effect for the public to share private-led information rather than centralized unilateral delivery of information. This study analyzes the role of private-led information provision in infectious disease situations. To this end, topic modeling and sentiment analysis is carried out on online reviews of all COVID-19-related applications in Google Playstore provided by the Korean government and the private. The results showed that the user's evaluation of private apps, which were used from the early stage of COVID-19, was much higher than the apps provided by the government. In particular, users responded more positively to private apps than government apps in all aspects such as reliability of information, risk avoidance, timeliness, usefulness, and stability. Based on these results, a post-monitoring system is recommended rather than a pre-block of all private apps.

• Structural Engineering and Mechanics
• /
• v.86 no.6
• /
• pp.715-730
• /
• 2023

Broad studies have addressed the issue of structural element damage identification, however, rubber bearing, as a key component of load transmission between the superstructure and substructure, is essential to the operational safety of a bridge, which should be paid more attention to its health condition. However, regarding the limitations of the traditional bearing damage detection methods as well as few studies have been conducted on this topic, in this paper, inspired by the model updating-based structural damage identification, a two-stage bearing damage identification method has been proposed. In the first stage, we deduce a novel bearing damage localization indicator, called element relative MSE, to accurately determine the bearing damage location. In the second one, the prior knowledge of bearing damage localization is combined with sailfish optimization (SFO) to perform the bearing damage estimation. In order to validate the feasibility, a numerical example of a 5-span continuous beam is introduced, also the noise robustness has been investigated. Meanwhile, the effectiveness and engineering applicability are further verified based on an experimental simply supported beam and actual engineering of the I-40 Bridge. The obtained results are good, which indicate that the proposed method is not only suitable for simple structures but also can accurately locate the bearing damage site and identify its severity for complex structure. To summarize, the proposed method provides a good guideline for the issue of bridge bearing detection, which could be used to reduce the difficulty of the traditional bearing failure detection approach, further saving labor costs and economic expenses.

• Proceedings of the KIPE Conference
• /
• 2013.11a
• /
• pp.63-64
• /
• 2013

Induction motors' faults detection is almost a popular topic among researchers. Monitoring the output of motors is a key factor in detecting these faults. (Short-time) Fourier, (continuous, discrete) wavelet, and extended Park vector transformations are among the methods for fault detection. One major deficiency of these methods is not being able to detect the severity of faults that carry low energy information, e.g. in ball bearing system failure, there is absolutely no way to detect the severity of fault using Fourier or wavelet transformations. In this paper, the authors have applied the Discrete Wavelet Transform (DWT) frequency-domain analysis to detect bearing faults in an induction motor. In other words, in discrete transform which the output signal is decomposed in several steps and frequency resolution increases considerably, the frequency-band analysis is performed and it will be verified that first of all, fault sidebands become more recognizable for detection in higher levels of decomposition, and secondly, the inner race bearing faults turn out easier in these levels; and all these matter because of eliminating the not-required high energy components in lower levels of decomposing.

• International Journal of Aeronautical and Space Sciences
• /
• v.17 no.4
• /
• pp.535-550
• /
• 2016

Securing the safety and the reliability of liquid-propellant rocket engines (LREs) for space vehicles is indispensable as engines consist of many complex components and operate under extremely high energy-dense conditions. Thus, health monitoring has become a mandatory requirement, especially for the reusable LREs that are currently being developed. In this context, a dynamic simulation program based on MATLAB/Simulink was developed in the current research on the Space Shuttle Main Engine (SSME), a partly reusable engine. Then, a series of fault simulations using this program was conducted: at a steady state operating condition (104% Rated Propulsion Level), various simulated fault conditions were artificially injected into the simulation models for the five major valves, the pumps, and the turbines of the SSME. The consequent effects due to each fault were analyzed based on the time responses of the major parameters of the engine. It is believed that this research topic is an essential pre-step for the development of fault detection and diagnosis algorithms for reusable engines in the future.

• Knowledge Management Research
• /
• v.16 no.4
• /
• pp.35-45
• /
• 2015

Fintech, which means the convergence of finance and information technology, becomes a hot topic in the financial sector. Through innovative activities on financial services, ICT(Information and Communication Technology) is integrated into the overall financial industry, and a new form of financial services could be expected to improve the existing financial system. On the other hand, fintech services are relatively vulnerable to security issues. Due to the process simplication and the channel fusion, the leakage of personal and financial informations, authentication bypass, phishing, and pharming are getting more concerned. In this study we investigated the security risk of fintech services in the viewpoints of service provider, technology adoption, and security policy. The possible countermeasures to reduce those risks are suggested because security is an important criterion for selecting financial services. This study basically offers quantification of the potential security risks and step-by-step control measures about business processes in the fintech services. The suggested security model includes user authentication, terminal security, payment information protection, API(Application Programming Interface) security, and abnormal transaction monitoring. This study might contribute to an understanding of the security risks and some possible measures for mitigating those risks on the practical perspective.

• The Journal of Korean Society for School & Community Health Education
• /
• v.14 no.2
• /
• pp.59-73
• /
• 2013

Objectives: Health promotion policies have been developed and implemented in most developed countries. The purpose of this study is to compare the national health promotion plans among Korea, Japan and USA. Methods: Data were collected and involved overview of health promotion plans, formulation of policy, evaluation, monitoring and research, implementation in each countries. I got the some literatures over the governmental websites related to the health promotion. The data from each country were analyzed for comparison. Results: The goals of Healthy People 2020 are to attain high-quality, longer lives, to achieve health equity, to create social and physical environments, to promote quality of life across all life stages. Those of Healthy Japan 21 are increasing the year of healthy life and reducing health disparities. and Those of Health Plan 2020 are prolonging of healthy age and improvement of healthy equity. The number of topic areas and objectives of health promotion in each countries were different. Healthy People 2020 lacks participation of community people and stakeholders in the process of planning, impletation, evaluation. Conclusion: The planning models of health promotion were different among countries. But they reflect the social determinants of health. The health plan goals of Korea were similar to Japan. but were different from USA. The implementation and evaluation systems of USA and Japan were systematic and performed well than those of Korea.

• Tuberculosis and Respiratory Diseases
• /
• v.80 no.3
• /
• pp.230-240
• /
• 2017

Chronic obstructive pulmonary disease (COPD) results in high morbidity and mortality among patients both domestically and globally. The Korean clinical practice guideline for COPD was revised in 2014. It was drafted by the members of the Korean Academy of Tuberculosis and Respiratory Diseases, as well as participating members of the Health Insurance Review and Assessment Service, Korean Physicians' Association, and Korea Respiration Trouble Association. This revised guideline covers a wide range of topics, including the epidemiology, diagnosis, assessment, monitoring, management, exacerbation, and comorbidities of COPD in Korea. We drafted a guideline on COPD management by performing systematic reviews on the topic of management with the help of a meta-analysis expert. We expect this guideline will be helpful medical doctors treating patients with respiratory conditions, other health care professionals, and government personnel in South Korea.