• Journal of Biomedical Engineering Research
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• v.41 no.1
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• pp.8-13
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• 2020

To develop cardiovascular simulator capable of implementing pulse waves similar to the human body, accurate information about reflection wave is required. However, the conclusion is still not clear and various discussions are underway. In this study, the pulse wave velocity of the tube used in the experiment was first determined by measuring the pressure waves at two points in a single tube system with the experimental device to implement the pulse wave transmission of blood vessels, and the superposition time and characteristics of the reflection wave were confirmed. After that, an air chamber was set at the reflection site, and the effect of the change of air volume on the reflection wave was investigated. Finally, the effect of the number of branches connected to a single tube on the reflection wave was investigated. The superposition time of the reflection wave can be controlled by the air volume of the air chamber, and the magnitude of the reflection wave is influenced by the number of reflection sites that generate the reflection wave. The results of this study may be of practical assistance to simulator researchers who want to implement pulse wave similar to clinical data. It is expected that the more results similar to clinical are provided, the greater the scope of the simulator's contribution to clinical cardiovascular research.

• Quality Improvement in Health Care
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• v.15 no.2
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• pp.107-120
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• 2009

Background : To estimate fall incidence rate and associated factors in inpatients from a general hospital. Method : The data were collected from 104 fall incident reports developed by the patient safety committee in a general hospital in Seoul from 01 January 2007 to 31 December 2008. Information included general characteristics of patients, factors related to fall, types, places, circumstances and outcomes of fall. Result : The incidence rate of fall, which was 4.4 per 1,000 total discharged patients and 0.5 per 1,000 patient-days, was much lower than that of several hospitals in the United States. The difference may reflect the different incidence reporting system of each hospital. Fall-prone patients were, in general, $$\geq_-$$65 years of age, had an alert mental status, were ambulatory with some assistance, and were dependent on and ambulatory device. High incidence of falls was associated with patients with circulatory disease. The majority of fall events usually occurred in bed or at the bedside in the patient's room, and occurred more often during the night than during the day or evening. Risk factors of fall were use of drugs (antihypertensive or neuropsychiatric drugs) and environmental factors (e.g., overly high bed height, surrounding objects, inadequate fitness shoes and slippery floor). Physical injury occurred in 43.3% of fall events, which typically required diagnosis of injury and treatment such as suturing. Risk factors for repeated falls were use of a neuropsychiatric drug (odds ratio=13.9) and gait disturbance (odds ratio=91.2). Risk factors for fall-related injury were alert mental status (odds ratio=3.3 times more likely to fall than those who were drowsy or in a stupor) and general weakness(odds ratio=3.3 times more likely to fall than those who were not generally weak). Conclusion : Medical and nursing staff should be aware of the fall risk factors of hospitalized patients and should intensively pursue preventative strategies. Development of fall prevention education based on these results is recommended.

• Journal of Biomedical Engineering Research
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• v.27 no.5
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• pp.274-281
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• 2006

In this paper, we propose a ubiquitous $SaO_2$ monitoring system for patients using oxygen therapy. For these patients, the ability to monitor oxygen saturation ubiquitously is very important fur accurate adjustment of ventilator's flow rate to match the patient's time-varying requirements with the shortest lag time possible. We have developed a portable device to measure $SaO_2$ and transmit it to hospital in real-time or in store-and-forward mode through the integration of $Bluetooth^{TM}$ technology and the code division multiple access (CDMA) cellular network. We also developed software for doctors to receive and manage the patients' $SaO_2$ information. Performance of the developed system was evaluated as acceptable by assessing the accuracy of the measured oxygen saturation value and the stability of communication network. Test results in real clinical setting demonstrate that our system is feasible for immediate use in home oxygen therapy.

• Journal of KIISE:Software and Applications
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• v.30 no.12
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• pp.1239-1246
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• 2003

Registration is the process aligning the range data sets from different views in a common coordinate system. In order to achieve a complete 3D model, we need to refine the data sets after coarse registration. One of the most popular refinery techniques is the iterative closest point (ICP) algorithm, which starts with pre-estimated overlapping regions. This paper presents an improved ICP algorithm that can automatically register multiple 3D data sets from unknown viewpoints. The sensor projection that represents the mapping of the 3D data into its associated range image is used to determine the overlapping region of two range data sets. By combining ICP algorithm with the sensor projection constraint, we can make an automatic registration of multiple 3D sets without pre-procedures that are prone to errors and any mechanical positioning device or manual assistance. The experimental results showed better performance of the proposed method on a couple of 3D data sets than previous methods.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.6
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• pp.82-89
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• 2010

Ankle-foot orthosis with an artificial pneumatic muscle which is intended for the assistance of plantarfelxion torque was developed. In this study, power pattern of the device in the various pneumatics and the effectiveness of the system were investigated. The pneumatic power was provided by ankle-foot orthosis controlled by user‘s physiological signal, that is, muscular stiffness in soleus muscle. This pneumatic power can assist plantarflexion torque of ankle joint. The subjects performed maximal voluntary isokinetic plantarflexion motion on a biodexdynamometer in different pneumatics, and they completed three conditions: 1) without wearing the orthosis, 2) wearing the orthosis with artificial muscles turned off, 3) wearing the orthosis activated under muscular stiffness control. Through these experiments, we confirmed the effectiveness of the orthosis and muscular stiffness control using the analyzing isokinetic plantarflexion torque. The experimental results showed that isokinetic torques of plantarflexion motion of the ankle joints gradually increased in incremental pneumatic. The effectiveness of the orthosis was -7.26% and the effectiveness of the muscular stiffness control was 17.83% in normalized isokinetic plantarflexion torque. Subjects generated the less isokinetic torques of the ankle joints in wearing the orthosis with artificial muscles turned off, but isokinetic torques were appropriately reinforced in condition of wearing the orthosis activated under muscular stiffness control(17.83%) compared to wearing the orthosis(-7.26%). Therefore, we respect that developed powered orthosis is applied in the elderly that has weak muscular power as the rehabilitation equipment.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.30-36
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• 2008

Recently, ere are many researches to improve the quality of e medical service such as Point of care (POC). To improve the quality of the medical service, not only good medical device but also more man power is required. Especially, the number of nurses are very few in Korea that is almost the lowest rank compared to OECD countries. If the simple repetition works of the nurse could be removed, it is possible to use the skillful nurse for other works and provide better quality services. There are many simple repetition works which the nurses have to do, such as replacing the ringer's solution. To replace the ringer's solution automatically, it is necessary to detect residual quantity of the ringer's solution. In this paper, image processing is used to detect the residual quantity of ringer's solution, and modified self quotient image (SQI) algorithm is used to strong background lights. After modified SQI algorithm, the simple histogram accumulation is done to find the residual quantity of the ringer's solution. The implemented algorithm could be use to replace the ringer's solution automatically or alarm to the nurses to replace the solution.

• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.289-295
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• 2013

Although low-level laser therapy (LLLT) has been a valuable therapeutic technology in the clinic, its efficacy may be reduced in deep tissue layers due to strong light scattering which limits the photon density. In order to enhance the photon density in deep tissue layers, this study developed an optical tissue clearing (OTC) laser probe (OTCLP) system which can utilize four different OTC methods: 1) tissue temperature control from 40 to $10^{\circ}C$; 2) laser pulse frequency from 5 to 30 Hz; 3) glycerol injection at a local region; and 4) a combination of the aforementioned three methods. The efficacy of the OTC methods was evaluated and compared by investigating laser beam profiles in ex-vivo porcine skin samples. Results demonstrated that total (peak) intensity at full width at half maximum of laser beam profile when compared to control data was increased: 1) 1.21(1.39)-fold at $10^{\circ}C$; 2) 1.22 (1.49)-fold at a laser pulse frequency of 5 Hz; 3) 1.64 (2.41)-fold with 95% glycerol injection; 4) 1.86 (3.4)-fold with the combination method. In conclusion, the OTCLP system successfully improved the laser photon density in deep tissue layers and may be utilized as a useful tool in LLLT by increasing laser photon density.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.81-90
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• 2003

Existing web-based system management software solutions show some limitations in time and space. Moreover, they possess such as shortcomings unreliable error message announcements and difficulties with real-time assistance suppers and emergency measures. In order to solve these deficiencies, Wireless Remote Control System was designed and implemented. Wireless Remote Control System is able to manage and monitor remote systems by using mobile communication devices for instantaneous control. The implementation of Wireless Remote Control System leads to these security Problems as well as solutions to aforementioned issues with existing web-based system management software solutions. Therefore, this paper has focused on the security matters related to Wireless Remote Control System. The designed security functions include mobile device user authentication and target system access control. For security verification of these security functions introduced CPN(Coloured Petri Nets) which is capable of expressing every possible state for each stage. And then in this paper was verified its security through PI(Place Invariant) based on CPN(Coloured Petri Nets). The CPN expression and analysis method of the proposed security function can also be a useful method for analyzing other services in the future.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.537-544
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• 2022

As the penetration of electric vehicles and development of new models, user experience factors are getting more important in designing connectivity systems for car infotainment services. The primary object of this study is to identify commonalities and differences by comparing user experience factors in the Korean and US electric vehicle markets. This study derived connectivity keywords by text mining the vehicle introduction on the market in each country, and performed centrality, cluster analysis and visualization mapping using the semantic network analysis. As a result, the Korean new electric vehicle connectivity service mainly focused on driving functions such as driving, parking assistance, and charging, while US focused on device connection, convenience function control, app use, entertainment viewing. Based on the analysis, this study presented the practical implications in marketing, system design, and HMI design.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.459-464
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• 2024

The purpose of this study is to design a toilet lifting seat to prevent falls accidents in the elderly while using the toilet. Prior to design, laws and national standards related to restroom use were investigated and the available space for the assistive devices to be installed was determined. In additions, considering the body size and operating range of the elderly, the optimal final position of the toilet seat is set so that users can use it more safely and conveniently without external help. Moreover, in order to provide an effective standing assistance function, a complex 4-bar link structure was applied to enable simultaneous seat elevation and angle adjustment when operating the device, and the appropriate link shape and dimensions were determined using a linkage program and UG NX. FEA analysis using ANSYS Workbench is performed to ensure the robustness of the stretched linkage and the feasibility of the lifting seat is verified through fabrication.