• Smart Structures and Systems
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• v.30 no.1
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• pp.75-88
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• 2022

Engineering structures in operation essentially belong to time-varying or nonlinear structures and the resultant response signals are usually non-stationary. For such time-varying structures, it is of great importance to extract time-dependent dynamic parameters from non-stationary response signals, which benefits structural health monitoring, safety assessment and vibration control. However, various traditional signal processing methods are unable to extract the embedded meaningful information. As a newly developed technique, variational mode decomposition (VMD) shows its superiority on signal decomposition, however, it still suffers two main problems. The foremost problem is that the number of modal components is required to be defined in advance. Another problem needs to be addressed is that VMD cannot effectively separate non-stationary signals composed of closely spaced or overlapped modes. As such, a new method named generalized adaptive variational modal decomposition (GAVMD) is proposed. In this new method, the number of component signals is adaptively estimated by an index of mean frequency, while the generalized demodulation algorithm is introduced to yield a generalized VMD that can decompose mode overlapped signals successfully. After that, synchrosqueezing wavelet transform (SWT) is applied to extract instantaneous frequencies (IFs) of the decomposed mono-component signals. To verify the validity and accuracy of the proposed method, three numerical examples and a steel cable with time-varying tension force are investigated. The results demonstrate that the proposed GAVMD method can decompose the multi-component signal with overlapped modes well and its combination with SWT enables a successful IF extraction of each individual component.

• The Journal of Asian Finance, Economics and Business
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• v.10 no.2
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• pp.153-161
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• 2023

This study's principal goal is to find the interrelation between transparency & disclosure (TD) and the healthcare sector's firm valuation (FV). The paper uses the market-to-book (MTB) ratio and market capitalization as proxies, where sales measure act as a control variable. Dynamic panel data regression (PD) is the method applied for analyzing data. Data pertains to 10 healthcare companies gathered over five years (2016-2020). Results imply that TD has a negative and significant influence on the FV, where market capitalization acts as a proxy for valuation. This association indicates that a greater degree of TD diminishes FV. TD is also reported to have a negative and insignificant association with MTB. Therefore, TD does not influence FV. The findings of this paper have significant practical implications. Results can help policymakers determine mandatory disclosure levels that are not detrimental to the healthcare sector. Managers and analysts must also analyze the dimensions of disclosure that can negatively impact the firm's valuation and make decisions regarding TD accordingly. This is the first study to assess the influence of TD on the FV of the Indian healthcare sector, which makes it unique. This study is limited to the healthcare sector, which is its shortcoming.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.1
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• pp.127-137
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• 2022

PURPOSE: This study sought to evaluate muscle activity and foot pressure during gait, and balance in female college students with genu valgum. METHOD: Participants were assigned based on their Q-angle to genu valgum group greater than 20° (GVG, n = 12), unilateral genu valgum group greater than 20° (UVG, n = 11), and control group (CON, n = 13). All subjects were evaluated for balance (Trace length, C90 area, C90 angle, and the Romberg test), muscle activity (gluteus medius; GM, tensor fasciae latae; TFL, vastus medialis; VM, vastus lateralis; VL, biceps femoris; BF, gastrocnemius; GCM and tibialis anterior; TA) and foot pressure (F/F ratio, R/F ratio, Hallux, 2~5 toe, 1st MT, 2~4 MT, 5th MT, Midfoot, M/heel, and L/heel) during gait. RESULTS: Romberg test showed significantly increased loss of balance in the UVG group compared with the CON. In the forward position, the imbalance was significantly increased in the UVG and GVG groups compared to the CON. Muscle activity of VL, GCM, and TA significantly increased in the GVG group compared with the CON. Static foot pressure, 1st MT significantly increased in the GVG compared to the CON group. The 5th MT significantly decreased in the CON compared with the GVG group. The R/F ratio significantly decreased in the GVG compared to the CON group. In dynamic foot pressure, the 2~5 toe significantly increased in the GVG compared with the UVG group. The left 5th MT significantly decreased in the UVG compared with the CON and GVG groups. CONCLUSION: These results indicate that genu valgum has a negative effect on balance, muscle activity, and foot pressure during gait in female college students.

• Clinical and Experimental Pediatrics
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• v.65 no.3
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• pp.142-149
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• 2022

Background: Individuals with Down syndrome present with several impairments such as hypotonia, ligament laxity, decreased muscle strength, insufficient muscular cocontraction, inadequate postural control, and disturbed proprioception. These factors are responsible for the developmental challenges faced by children with Down syndrome. These individuals also present with balance dysfunctions. Purpose: This systematic review aims to describe the motor dysfunction and balance impairments in children and adolescents with Down syndrome. Methods: We searched the Scopus, ScienceDirect, MEDLINE, Wiley, and EBSCO databases for observational studies evaluating the motor abilities and balance performance in individuals with Down syndrome. The review was registered on PROSPERO. Results: A total of 1,096 articles were retrieved; after careful screening and scrutinizing against the inclusion and exclusion criteria, 10 articles were included in the review. Overall, the children and adolescents with Down syndrome showed delays and dysfunction in performing various activities such as sitting, pulling to stand, standing, and walking. They also presented with compensatory mechanisms to maintain their equilibrium in static and dynamic activities. Conclusion: The motor development of children with Down syndrome is significantly delayed due to structural differences in the brain. These individuals have inefficient compensatory strategies like increasing step width, increasing frequency of mediolateral center of pressure displacement, decreasing anteroposterior displacement, increasing trunk stiffness, and increasing posterior trunk displacement to maintain equilibrium. Down syndrome presents with interindividual variations; therefore, a thorough evaluation is required before a structured intervention is developed to improve motor and balance dysfunction.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.95-103
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• 2022

As 5G mobile communication services gradually expand in P2P (peer-to-peer) or D2D (device-to-device) applications, traffic-oriented stream control such as YouTube streaming is emerging as an important technology. In D2D communication, the type of data stream most frequently transmitted by users is a video stream, which has the characteristics of a large-capacity transport stream. In a D2D communication environment, this type of stream not only provides a cause of traffic congestion, but also degrades the quality of service between D2D User Equipments (DUEs). In this paper, we propose a Traffic-Oriented Stream Scheduling (TOSS) scheme to minimize the interruption of dynamic media streams such as video streams and to optimize streaming service quality. The proposed scheme schedules the media stream by analyzing the characteristics of the media stream and the traffic type in the bandwidth of 3.5 GHz and 28 GHz under the 5G gNB environment. We examine the performance of the proposed scheme through simulation, and the simulation results show that the proposed scheme has better performance than other comparative methods.

• Wind and Structures
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• v.36 no.4
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• pp.221-236
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• 2023

The lateral component of turbulence and the vortices shed in the wake of a structure result in introducing dynamic wind load in the acrosswind direction and the resulting level of motion is typically larger than the corresponding alongwind motion for a dynamically sensitive structure. The underlying source mechanisms of the acrosswind load may be classified into motion-induced, buffeting, and Strouhal components. This study proposes a frequency domain framework to decompose the overall load into these components based on output-only measurements from wind tunnel experiments or full-scale measurements. First, the total acrosswind load is identified based on measured acceleration response by solving the inverse problem using the Kalman filter technique. The decomposition of the combined load is then performed by modeling each load component in terms of a Bayesian filtering scheme. More specifically, the decomposition and the estimation of the model parameters are accomplished using the unscented Kalman filter in the frequency domain. An aeroelastic wind tunnel experiment involving a tall circular cylinder was carried out for the validation of the proposed framework. The contribution of each load component to the acrosswind response is assessed by re-analyzing the system with the decomposed components. Through comparison of the measured and the re-analyzed response, it is demonstrated that the proposed framework effectively decomposes the total acrosswind load into components and sheds light on the overall underlying mechanism of the acrosswind load and attendant structural response. The delineation of these load components and their subsequent modeling and control may become increasingly important as tall slender buildings of the prismatic cross-section that are highly sensitive to the acrosswind load effects are increasingly being built in major metropolises.

• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.149-158
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• 2023

With the global paradigm shift towards climate change, the shipbuilding industry is also considering propulsion systems that utilize eco-friendly fuels various propulsion systems are gaining attention as a result. In conventional propulsion systems, typically consisting of propellers and rudders, have evolved into a diverse range of systems due to the development of a special propulsion system known as the azimuth thruster. While azimuth thrusters were previously commonly installed on tugboats, they are now extensively used on offshore plant operation ships equipped with dynamic positioning systems. However, these azimuth thrusters require different steering methods compared to conventional propulsion systems, leading to a significant learning curve for the crew members boarding such vessels. Furthermore the availability of education related to these special propulsion systems is limited. This study aims to analyze accidents caused by inadequate control of vessels equipped with azimuth thrusters using the STAMP technique. And it proposes the necessity of standard steering commands for the safe operation of vessels equipped with special propellers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.4
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• pp.1216-1233
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• 2023

Conventional occupational therapy (OT) is conducted under the observation of an occupational therapist, and there are limitations in measuring and analyzing details such as degree of hand tremor and movement tendency, so this important information may be lost. It is therefore difficult to identify quantitative performance indicators, and the presence of observers during performance sometimes makes the subjects feel that they have to achieve good results. In this study, by using the Unity3D and artificial intelligence (AI) speaker, we propose a system that allows the subjects to steadily use it by themselves and helps the occupational therapist objectively evaluate through quantitative data. This system is based on the OT of the sensory integration approach. And the purpose of this system is to improve children's activities of daily living by providing various feedback to induce sensory integration, which allows them to develop the ability to effectively use their bodies. A dynamic OT cognitive assessment tool for children used in clinical practice was implemented in Unity3D to create an OT environment of virtual space. The Leap Motion Controller allows users to track and record hand motion data in real time. Occupational therapists can control the user's performance environment remotely by connecting Unity3D and AI speaker. The experiment with the conventional OT tool and the system we proposed was conducted. As a result, it was found that when the system was performed without an observer, users can perform spontaneously and several times feeling ease and active mind.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.871-874
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• 2011

The fast emerging of network technology and the high demand of computing resources have prompted many organizations to outsource their storage and computing needs. Cloud based storage services such as Microsoft's Azure and Amazon's S3 allow customers to store and retrieve any amount of data, at anytime from anywhere via internet. The scalable and dynamic of the cloud storage services help their customer to reduce IT administration and maintenance costs. No doubt, cloud based storage services brought a lot of benefits to its customer by significantly reducing cost through optimization increased operating and economic efficiencies. However without appropriate security and privacy solution in place, it could become major issues to the organization. As data get produced, transferred and stored at off premise and multi tenant cloud based storage, it becomes vulnerable to unauthorized disclosure and unauthorized modification. An attacker able to change or modify data while data inflight or when data is stored on disk, so it is very important to secure data during its entire life-cycle. The traditional cryptography primitives for the purpose of data security protection cannot be directly adopted due to user's lose control of data under off premises cloud server. Secondly cloud based storage is not just a third party data warehouse, the data stored in cloud are frequently update by the users and lastly cloud computing is running in a simultaneous, cooperated and distributed manner. In our proposed mechanism we protect the integrity, authentication and confidentiality of cloud based data with the encrypt- then-upload concept. We modified and applied proxy re-encryption protocol in our proposed scheme. The whole process does not reveal the clear data to any third party including the cloud provider at any stage, this helps to make sure only the authorized user who own corresponding token able to access the data as well as preventing data from being shared without any permission from data owner. Besides, preventing the cloud storage providers from unauthorized access and making illegal authorization to access the data, our scheme also protect the data integrity by using hash function.

• Atmosphere
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• v.32 no.1
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• pp.27-37
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• 2022

The Korean Integrated Model (KIM) forecast system was extended to assimilate Horizontal Line-Of-Sight (HLOS) wind observations from the Atmospheric Laser Doppler Instrument (ALADIN) on board the Atmospheric Dynamic Mission (ADM)-Aeolus satellite. Quality control procedures were developed to assess the HLOS wind data quality, and observation operators added to the KIM three-dimensional variational data assimilation system to support the new observed variables. In a global cycling experiment, assimilation of ALADIN observations led to reductions in average root-mean-square error of 2.1% and 1.3% for the zonal and meridional wind analyses when compared against European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) analyses. Even though the observable variable is wind, the assimilation of ALADIN observation had an overall positive impact on the analyses of other variables, such as temperature and specific humidity. As a result, the KIM 72-hour wind forecast fields were improved in the Southern Hemisphere poleward of 30 degrees.