• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.1
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• pp.1-14
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• 2020

Various policies and studies regarding use of PBSS (Public Bike Sharing System) and Programs (PBSP) have been conducted worldwide as the number systems or programs has increased. Although various phenomena and demands have been generated by the use of PBSS in everyday life, the majority of research and the policies in South Korea have been implemented focused on commuting life. The purpose of this study aimed to understand various PBSS demands using PBSS usage data in 2018 in the Yeouido districts through classifying usage patterns and analyzing features. The rental stations were classified into three types based on weekday/weekend usage rates. The usage of Yeouido's PBSS accounted for 4.3% of the total usage in Seoul Metropolitan City, while the number of PBSS rental stations accounted for 2% of all rental stations in the Seoul urban areas. Rental stations with a higher weekday utilization rates showed high utilization rates in all four seasons and were mainly distributed in work and residential areas. Other stations showed a concentrated usage pattern in spring (April-May) and autumn (September-October) seasons, and their locations were close to the entrance of nearby parks. Besides, renting and returning were often concentrated at certain rental stations for high weekend utilization as compared to the pattern of high weekday usage. Therefore, PBSS management and programs should be operated to reflect various usage demands rather than uniform PBSS operations. The result of this study is meaningful to provide basic data for effective PBSS operation by monitoring the demand for PBSS usage in spatio-temporal terms.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.446-452
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• 2016

The aircraft has to be considered for safety very importantly because of peculiarity of flight in the air, so it should be retained through proper inspection and maintenance not only in production phase but also in operating phase. Recently, it is using the latest technology as engineering approach not depending on human factor to determine on maintenance needs, and domestic production rotary aircraft also has the health & usage monitoring system to measure and to monitor major components. However, continued vibration exceedance phenomenon occurred in production and operation phase because of inappropriate thresholds, and it confirmed as false alarm which is not necessary to repair. In this paper, it is described that operational concept of HUMS, and especially it contains a study result for efficiency of aircraft operation and ultimately the improvement of flight safety by optimizing HUMS thresholds to determine efficiently necessity of maintenance under limited conditions and by establishing inspection/maintenance procedures when the re-designated thresholds exceedance occurred.

• International Journal of Computer Science & Network Security
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• v.22 no.12
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• pp.1-12
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• 2022

Besides unexpected growth perceived by IoT's, the variety and volume of threats have increased tremendously, making it a necessity to introduce intrusion detections systems for prevention and detection of such threats. But Intrusion Detection and Prevention System (IDPS) inside the IoT network yet introduces some unique challenges due to their unique characteristics, such as privacy inference, performance, and detection rate and their frequency in the dynamic networks. Our research is focused on the privacy inferences of existing intrusion prevention and detection system approaches. We also tackle the problem of providing unified a solution to implement the open-source IDPS in the IoT architecture for assessing the performance of IDS by calculating; usage consumption and detection rate. The proposed scheme is considered to help implement the human health monitoring system in IoT networks

• Journal of Environmental Impact Assessment
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• v.14 no.2
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• pp.83-96
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• 2005

Brominated flame retardants have the market share of 40%, comparing others because of their low cost and highly effective retardation against the flame. However, their toxic effects in human and properties of the accumulation in the environments have been issued among the international organization such as EU, OECD and etc. It, therefore, was surveyed the classification, toxic effects, and the usage of Brominated flame retardants, the trends for their managements in the world and Korea, and their contaminated levels in Korean Peninsula. In addition, the management directions for them were proposed. Penta, octa, and deca-BDE among brominated retardants will seem to be prohibited by the regulation as a flame retardants for plastics in Europe because of their toxic effects. Although Penta and Octa BDEs was used marginally in Korea, deca-BDE was 27% of brominated flame retardants (49,050 ton) which had been used in 2002. However, risk assessment for brominated retardants might not launched in Korea, yet. These reports demonstrate that toxic brominated retardants such as PBDEs will be assessed for their usage and the level of contamination in the environment in the area of the point sources like the industrial areas, incinerators and etc. However, the law to regulate the hazardous chemicals seems not to be dictated the monitoring of their contamination in the environment. We, therefore, suggest how to evaluate and to monitor the toxic contaminants with EIA (Environmental Impact Assessment) and LCA (Life Cycle Assessment) system. Further, to establish the management system of BFRs (such as the monitering of contamination levels in environments, life cycle assessment, and risk assessment for the toxic chemicals), It can be recommended the law to deal with the method analyzing chemicals will be established, which contains QA/QC (Quality Assurance and Quality Control) to evaluate the analytic capability of the companies to prepare EIS (Environment Impact Statement) or other institutes for analyzing chemicals.

• Smart Structures and Systems
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• v.24 no.2
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• pp.243-256
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• 2019

Determination of the most meaningful structural modes and gaining insight into how these modes evolve are important issues for long-term structural health monitoring of the long-span bridges. To address this issue, modal parameters identified throughout the life of the bridge need to be compared and linked with each other, which is the process of mode tracking. The modal frequencies for a long-span bridge are typically closely-spaced, sensitive to the environment (e.g., temperature, wind, traffic, etc.), which makes the automated tracking of modal parameters a difficult process, often requiring human intervention. Machine learning methods are well-suited for uncovering complex underlying relationships between processes and thus have the potential to realize accurate and automated modal tracking. In this study, Gaussian mixture model (GMM), a popular unsupervised machine learning method, is employed to automatically determine and update baseline modal properties from the identified unlabeled modal parameters. On this foundation, a new mode tracking method is proposed for automated mode tracking for long-span bridges. Firstly, a numerical example for a three-degree-of-freedom system is employed to validate the feasibility of using GMM to automatically determine the baseline modal properties. Subsequently, the field monitoring data of a long-span bridge are utilized to illustrate the practical usage of GMM for automated determination of the baseline list. Finally, the continuously monitoring bridge acceleration data during strong typhoon events are employed to validate the reliability of proposed method in tracking the changing modal parameters. Results show that the proposed method can automatically track the modal parameters in disastrous scenarios and provide valuable references for condition assessment of the bridge structure.

• Clinical and Experimental Pediatrics
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• v.51 no.9
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• pp.922-934
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• 2008

Developmental language disorder is the most common developmental disability in childhood, occurring in 5-8% of preschool children. Children learn language in early childhood, and later they use language to learn. Children with language disorders are at increased risk for difficulties with reading and written language when they enter school. These problems often persist through adolescence or adulthood. Early intervention may prevent the more serious consequences of later academic problems, including learning disabilities. A child's performance in specific speech and language areas, such as phonological ability, vocabulary comprehension, and grammatical usage, is measured objectively using the most recently standardized, norm-referenced tests for a particular age group. Observation and qualitative analysis of a child's performance supplement objective test results are essential for making a diagnosis and devising a treatment plan. Emphasis on the team approach system in the evaluation of children with speech and language impairments has been increasing. Evidence-based therapeutic interventions with short-term, long-term, and functional outcome goals should be applied, because there are many examples of controversial practices that have not been validated in large, controlled trials. Following treatment intervention, periodic follow-up monitoring by a doctor is also important. In addition, a systematized national health policy for children with speech and language disorders should be provided.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.2
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• pp.208-218
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• 2014

Objectives: The major objective of this study was to develop and validate a tier 1 exposure model utilizing worker exposure monitoring data and characteristics of worker activities routinely performed at construction sites, in order to estimate worker exposures without sampling. Methods: The Registration, Evaluation, Authorization and Restriction of Chemicals(REACH) system of the European Union(EU) allows the usage of exposure models for anticipating chemical exposure of manufacturing workers and consumers. Several exposure models have been developed such as Advanced REACH Tools(ART). The ART model is based on structured subjective assessment model. Using the same framework, a tier 1 exposure model has been developed. Worker activities at construction sites have been analyzed and modifying factors have been assigned for each activity. Korean Occupational Safety and Health Agency(KOSHA) accrued work exposure monitoring data for the last 10 years, which were retrieved and converted into exposure scores. A separate set of sampling data were collected to validate the developed exposure model. These algorithm have been realized on Excel spreadsheet for convenience and easy access. Results: The correlation coefficient of the developed model between exposure scores and monitoring data was 0.36, which is smaller than those of EU models(0.6~0.7). One of the main reasons explaining the discrepancy is poor description on worker activities in KOSHA database. Conclusions: The developed tier 1 exposure model can help industrial hygienists judge whether or not air sampling is required or not.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.8
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• pp.253-258
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• 2015

From the point of view of u-healthcare, heart rate is so useful for both illness for taking care of patients and wellness for improving the level of health and wellbeing. It is because heart rate is a significant clinical variable for all kinds of diseases as well as an indicator of the intensity of exercise. Recently, a number of various wearable heart rate monitors have been released to check people's status in the body by monitoring their heart rates. In addition, a number of smartphone applications have been released to conveniently monitor the status of exercise by using heart rate monitors. However, all of these applications are limited to a personal usage. In this paper, we will design a system to simultaneously monitor heart rates coming from multiple users in a real-time, and develop an Android application to apply the system. The application mainly features a simultaneous monitoring of heart rates coming from multiple users, allowing to be effectively applied to fitness centers.

• Electronics and Telecommunications Trends
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• v.37 no.2
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• pp.30-41
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• 2022

As the society is superaging, the number of patients with movement disabilities due to musculoskeletal or nervous system illness is rapidly increasing. To improve public health and reduce medical expenses, it is essential to develop rehabilitation systems that allow patients to resume their daily-life activities. However, the existing musculoskeletal illness diagnosis and rehabilitation method is limited in terms of precision and efficiency because it is based on an empirical diagnosis and prescription without regard for individual characteristics. To overcome these limits, it is critical to design a novel concept of routine rehabilitation therapy device that is capable of inducing musculoskeletal balance by the precise analysis of musculoskeletal usage patterns via the motion and the muscle activity tracking of linked muscles. This study introduces the trend of on-skin sensor device technology for routine musculoskeletal monitoring and therapy. For on-skin rehabilitation systems, skin-adhesive and stretchable motion/posture, electromyography, pressure sensors, small-size and low-power wireless sensor interfaces, and user-friendly rehabilitation contents based on new algorithms are combined.

• Smart Structures and Systems
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• v.30 no.4
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• pp.411-420
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• 2022

Monitoring large structures is a significant issue involving public health on which new studies are constantly carried out. Although the Global Navigation Satellite System (GNSS) is the most preferable method for measuring structural displacements, total stations, one of the classical geodetic instruments, are the first devices that come to mind in cases that require complementary usage and auxiliary measurement methods. In this study, the relative displacements of the structural movements of a tower were determined using robotic total stations (RTS) and GNSS. Two GNSS receivers and two RTS observations were carried out simultaneously for 10 hours under normal weather conditions. The spectral analysis of the GNSS data was performed using fast Fourier transform (FFT), and while the dominant modal frequencies were determined, the total station data were balanced with the least-squares technique, and the position and position errors were calculated for each measurement epoch. It has been observed that low-frequency structural movements can be determined by both methods. This result shows that total station measurements are a helpful alternative method for monitoring large structures in situations where measurements are not possible due to the basic handicaps of GNSS or where it is necessary to determine displacements with short observations.