• Journal of Power System Engineering
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• v.10 no.4
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• pp.153-158
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• 2006

최근 임상용 LVAD의 계속된 발전으로 인해 환자들의 삶이 연장되었다. 그러나 LVAD가 환자의 삶을 연장하였지만, 우심실 심부전증을 야기 시켰고, 결론적으로 환자들은 RVAD가 필요하게 되었다. 이러한 이유로 장시간 사용할 수 있는 BVAD의 도입이 요구 되어졌다. 최근 BVAD에 관련된 연구들을 보면 장시간 사용을 위한 원심 BVAD의 디자인과 BVAD에서의 누수 정도를 파악하는데 목적을 두고 있다. 따라서 본 논문에서는 BVAD의 누수를 파악하기 위한 속도 데이터와 용적당 흐름 비율의 계산을 CFD를 사용하여 해석적으로 조사하고자 하였다. CFD의 해석 결과 틈새부위의 회전수가 증가 할수록 혈액의 흐름을 방해하는 역류가 증가하고 유량도 줄어들어, 틈새부위의 누수량이 회전속도의 변화에 의존된다는 것을 확인 할 수 있었다.

• The Korean journal of internal medicine
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• v.34 no.1
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• pp.11-43
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• 2019

Heart failure (HF) is an important cardiovascular disease because of its increasing prevalence, significant morbidity, high mortality, and rapidly expanding health care cost. The number of HF patients is increasing worldwide, and Korea is no exception. There have been marked advances in definition, diagnostic modalities, and treatment of HF over the past four decades. There is continuing effort to improve risk stratification of HF using biomarkers, imaging and genetic testing. Newly developed medications and devices for HF have been widely adopted in clinical practice. Furthermore, definitive treatment for end-stage heart failure including left ventricular assist device and heart transplantation are rapidly evolving as well. This review summarizes the current state-of-the-art management for HF and the emerging diagnostic and therapeutic modalities to improve the outcome of HF patients.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.3
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• pp.253-260
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• 2021

Therapeutic injections into the craniofacial region can be a complex procedure because of the nature of its anatomical structure. This technical note demonstrates a process for creating an extra-oral template to inject therapeutic substances into the temporomandibular joint and the lateral pterygoid muscle. The described process involves merging cone-beam computed tomography data and extra-oral facial scans obtained using a mobile device to establish a correlated data set for virtual planning. Virtual injection points were simulated using existing dental implant planning software to assist clinicians in precisely targeting specific anatomical structures. A template was designed and then 3D printed. The printed template showed adequate surface fit. This innovative process demonstrates a potential new clinical technique. However, further validation and in vivo trials are necessary to assess its full potential.

• Smart Structures and Systems
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• v.30 no.6
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• pp.649-659
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• 2022

Structural Health Monitoring (SHM) researchers have identified Augmented Reality (AR) as a new technology that can assist inspections. Post-seismic structural inspections are conducted to evaluate the safety level of the damaged structures. Quantification of nearby structural changes over short-term and long-term periods can provide building inspectors with information to improve their safety. This paper proposes a Time Machine Measure (TMM) application based on an Augmented Reality (AR) Head-Mounted-Device (HMD) platform. The primary function of TMM is to restore the saved meshes of a past environment and overlay them onto the real environment so that inspectors can intuitively measure dynamic structural deformation and other environmental movements. The proposed TMM application was verified by demo experiments simulating a real inspection environment.

• Journal of Biomedical Engineering Research
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• v.24 no.1
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• pp.9-13
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• 2003

An assist device was developed to identify the epidural space by continously monitoring the air-filled catheter pressure. The pressure signal appropriately amplified and filtered enabled to alarm the needle introduction into the epidural space by thresholding detection. Ten LEDs provided a visual change of catheter pressure before alarming for user convenience. Clinical trials were performed in 30 patients with 83% success rate at the first trial. When failed, the second trial was enough for successful anesthesia. The air volume introduced during each anesthesia was less than 1ml, causing side effects. Air filling of the catheter could also minimize infection possibility. Therefore, the present device guarantees safe anesthesia with user convenience.

• International Journal of Computer Science & Network Security
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• v.22 no.8
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• pp.328-342
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• 2022

The Internet of Things (IoT) is a technology that offers lucrative services in various industries to facilitate human communities. Important information on people and their surroundings has been gathered to ensure the availability of these services. This data is vulnerable to cybersecurity since it is sent over the internet and kept in third-party databases. Implementation of data encryption is an integral approach for IoT device designers to protect IoT data. For a variety of reasons, IoT device designers have been unable to discover appropriate encryption to use. The static support provided by research and concerned organizations to assist designers in picking appropriate encryption costs a significant amount of time and effort. IoTES is a web app that uses machine language to address a lack of support from researchers and organizations, as ML has been shown to improve data-driven human decision-making. IoTES still has some weaknesses, which are highlighted in this research. To improve the support, these shortcomings must be addressed. This study proposes the "IoTES with Security" model by adding support for the security level provided by the encryption algorithm to the traditional IoTES model. We evaluated our technique for encryption algorithms with available security levels and compared the accuracy of our model with traditional IoTES. Our model improves IoTES by helping users make security-oriented decisions while choosing the appropriate algorithm for their IoT data.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.72-79
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• 2022

Piezoelectric energy harvesting technologies, which can be used to convert the electricity from the mechanical energy, have been developed in order to assist or power the wearable electronics. To realize non-toxic and biocompatible electronics, the lead-free (Ba_0.85Ca_0.15)(Ti_0.90Zr_0.10)O₃ (BCTZ) nanoparticles (NPs) are being studied with a great attention as flexible energy harvesting device. Herein, piezoelectric hybrid nanocomposites were fabricated using BCTZ NPs-embedded poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] matrix to improve the performance of flexible energy harvester. Output performance of the fabricated energy device was investigated by the well-optimized measurement system during the periodically bending and releasing motions. The generated open-circuit voltage and the short-circuit current of the piezoelectric hybrid nanocomposite-based energy harvester reached up to ~15 V and ~1.1 ㎂, respectively; moreover, the instantaneous power of 3.5 ㎼ is determined from load voltage and current at the external load of 20 MΩ. This research is expected to cultivate a new approach to high-performance wearable self-powering electronics.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.54-60
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• 2008

The atomization characteristics of the dual air supplying twin-fluid nozzle were investigated experimentally using PIV and PDA systems. The two-fluid nozzle is composed of three main parts: the feeding injector to supply fluid that is controlled by a PWM (pulse-width modulation) mode, the adaptor as a device with the ports for supplying the carrier and assist air and the main nozzle to produce the spray. The main nozzle has the swirl tip with four equally spaced tangential slots, which give the injecting fluid an angular momentum. The angle of the swirl tip varied with 0$^{\circ}$ 30$^{\circ}$, 60$^{\circ}$ and 90$^{\circ}$, and the ratios of carrier air to assist air and ALR(total air to liquid) were 0.55 and 1.23, respectively. The macroscopic behavior of the spray was investigated using PIV system, and the mean velocity, turbulent intensity and SMD distributions of the sprays were measured using PDA system. As the results, the mean axial velocity at the spray centerline decrease with the increase of the swirl angle. The turbulent intensities of the axial and radial velocity were increased with the increase of the swirl angle. The mean SMD (Sauter mean diameter) of the radial direction along the axial distance shows the lowest value at the swirl angle of 60$^{\circ}$.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.14-21
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• 2014

In this paper, we devise a new ontology-based context-aware system to recognize the smart car information, in which driver's intent is utilized by information of car, driver, environment as well as driving state, driver state. So proposed system can handle dynamically risk changes by adding real-time situational awareness information. We utilize the camera image recognition technology for context-aware intelligent vehicle driving information, and implement information acquisition scheme OBD-II protocol to acquire vehicle's information. Experiments confirm that the proposed advanced driver safety assist system outperforms the conventional system, which only utilizes the information of vehicle, driver, and environmental information, to support the service of a high-speed driving, lane-departure service and emergency braking situation awareness.

• The Korean Journal of Rehabilitation Nursing
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• v.13 no.1
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• pp.23-31
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• 2010

Purpose: The purpose of this study were to describe the level of activities of daily living (ADLs) and fatigue of stroke patients and to identify related factors of ADLs and fatigue. Method: A sample of 132 were used who were recovering from stroke. The face-to-face interviews were conducted to collect data. The levels of ADLs and fatigue were evaluated using the Modified Barthel Index and Kim's fatigue scale respectively. A series of t-test and analysis of variance analyses were conducted to examine study purposes using SPSS 15.0. Results: The levels of fatigue and ADLs were 65.6 (SD=16.52) and 74.6 (SD=22.32) respectively. Significantly poorer ADLs were found: women (t=2.05, p=.001), older people aged ${\geq}$ 70 years (F=2.74, p=.046), the duration of onset (F=4.34, p=.006), the use of assist devices (F=35.64, p<.001), the parts of paralysis (F=4.25, p=.007), the time to attack (F=3.34, p=.039), and accompanying symptoms (F=15.23, p<.001). There was a significant difference in fatigue with patients with lower accompanying symptoms having lower fatigue (F=11.08, p<.001). Conclusion: These findings suggest gender, the duration from onset, the use of assist device, the parts of paralysis, the time to attack and accompanying symptoms were significant factors of the ADLs and fatigue post stroke. These factors should be considered when developing and testing nursing intervention programs for stroke survivors.