• Journal of Positioning, Navigation, and Timing
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• 제11권2호
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• pp.119-126
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• 2022

This paper presents a method to reduce the vibration-induced noise effect of an inertial measurement device mounted on a self-driving vehicle. The inertial sensor used in the GNSS/INS integrated navigation system of a self-driving vehicle is fixed directly on the chassis of vehicle body so that its navigation output is affected by the vibration of the vehicle's engine, resulting in the degradation of the navigational performance. Therefore, these effects must be considered when mounting the inertial sensor. In order to solve this problem, this paper proposes to use an in-house manufactured vibration suppression device and analyzes its impact on reducing the vibration effect. Experimental test results in a static scenario show that the vibration-induced noise effect is more clearly observed in the lateral direction of the vehicle, but can be effectively suppressed by using the proposed vibration suppression device compared to the case without it. In addition, the dynamic positioning test scenario shows the position, speed, and posture errors are reduced to 74%, 67%, and 14% levels, respectively.

• Archives of Plastic Surgery
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• 제50권2호
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• pp.156-159
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• 2023

Breast implants whether used for cosmetic or reconstructive purposes can be placed in pockets either above or below the pectoralis major muscle, depending on clinical circumstances such as subcutaneous tissue volume, history of radiation, and patient preference. Likewise, cardiac implantable electronic devices (CIEDs) can be placed above or below the pectoralis major muscle. When a patient has both devices, knowledge of the pocket location is important for procedural planning and for durability of device placement and performance. Here, we report a patient who previously failed subcutaneous CIED placement due to incision manipulation with prior threatened device exposure requiring plane change to subpectoral pocket. Her course was complicated by submuscular migration of the CIED into her breast implant periprosthetic pocket. With subcutaneous plane change being inadvisable due to patient noncompliance, soft tissue support of subpectoral CIED placement with an acellular biologic matrix (ABM) was performed. Similar to soft tissue support used for breast implants, submuscular CIED neo-pocket creation with ABM was performed with durable CIED device positioning confirmed at 9 months postprocedure.

• 지능정보연구
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• 제17권2호
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• pp.119-128
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• 2011

최근 사용자 정보와 주변 환경의 정보를 수집할 수 있는 센서의 기술과 휴대 디바이스의 성능이 매우 발달되어 왔다. 이러한 기술 발달로 인해 사용자는 매우 다양한 콘텐츠를 이용할 수 있게 되었다. 그러나 사용자가 휴대한 디바이스의 특성에 따라 이용할 수 있는 콘텐츠가 제한적이다. 이것을 해결하기 위해 하나의 콘텐츠를 여러 디바이스에서 사용하기 위한 연구가 활발히 진행 중이다. 본 연구에서는 사용자 주변의 센서를 통한 다양한 정보를 수집하여 사용자의 상황에 맞는 특정 콘텐츠를 선정하고, 선정된 콘텐츠를 사용자가 휴대한 디바이스 특성에 맞게 변환하여 서비스를 제공하는 시스템을 제안한다.

• 제어로봇시스템학회논문지
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• 제15권3호
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• pp.315-322
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• 2009

This paper explains a control and navigation algorithm of a 6-DOF gait rehabilitation robot, which can allow a patient to navigate in virtual reality (VR) by upper and lower limbs interactions. In gait rehabilitation robots, one of the important concerns is not only to follow the robot motions passively, but also to allow the patient to walk by his/her intention. Thus, this robot allows automatic walking velocity update by estimating interaction torques between the human and the upper limb device, and synchronizing the upper limb device to the lower limb device. In addition, the upper limb device acts as a user-friendly input device for navigating in virtual reality. By pushing the switches located at the right and left handles of the upper limb device, a patient is able to do turning motions during navigation in virtual reality. Through experimental results of a healthy subject, we showed that rehabilitation training can be more effectively combined to virtual environments with upper and lower limb connections. The suggested navigation scheme for gait rehabilitation robot will allow various and effective rehabilitation training modes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권4호
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• pp.1415-1435
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• 2018

Resource allocation in device-to-device (D2D) aided cellular systems, in which the proximity users are allowed to communicate directly with each other without relying on the intervention of base stations (BSs), is investigated in this paper. A new uplink resource allocation policy is proposed by exploiting the relationship between D2D-access probability and channel gain among variant devices, such as cellular user equipments (CUEs), D2D user equipments (DUEs) and BSs, etc., under the constraints of their minimum signal to interference-plus-noise ratio (SINR) requirements. Furthermore, the proposed resource-allocation problem can be formulated as the cost function of "maximizing the number of simultaneously activated D2D pairs subject to the SINR constraints at both CUEs and DUEs". Numerical results relying on system-level simulations show that the proposed scheme is capable of substantially improving both the D2D-access probability and the network throughput without sacrificing the performance of conventional CUEs.

• 조명전기설비학회논문지
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• 제29권3호
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• pp.81-87
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• 2015

In order to effectively protect electrical and electronic circuits which are extremely susceptible to lightning surges, multi-stage surge protection circuits are required. This paper presents the operational characteristics of the two-stage hybrid surge protection circuit in extra-low voltage DC power lines. The hybrid surge protective device consists of the gas discharge tube, transient voltage suppressor, and series inductor. The response characteristics of the proposed hybrid surge protective device to combination waves were investigated. As a result, the proposed two-stage surge protective device to combination wave provides the tight clamping level of less than 50V. The firing of the gas discharge tube to lightning surges depends on the de-coupling inductance and the rate-of-change of the current flowing through the transient voltage suppressor. The coordination between the upstream and downstream components of the hybrid surge protective device was satisfactorily achieved. The inductance of a de-coupler in surge protective circuits for low-voltage DC power lines, relative to a resistance, is sufficiently effective. The voltage drop and power loss due to the proposed surge protective device are ignored during normal operation of the systems.

• Journal of Information Processing Systems
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• 제6권3호
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• pp.347-358
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• 2010

This paper presents a measurement system for 3D hand-drawn gesture motion. Many pen-type input devices with Inertial Measurement Units (IMU) have been developed to estimate 3D hand-drawn gesture using the measured acceleration and/or the angular velocity of the device. The crucial procedure in developing these devices is to measure and to analyze their motion or trajectory. In order to verify the trajectory estimated by an IMU-based input device, it is necessary to compare the estimated trajectory to the real trajectory. For measuring the real trajectory of the pen-type device, a PHANToMTM haptic device is utilized because it allows us to measure the 3D motion of the object in real-time. Even though the PHANToMTM measures the position of the hand gesture well, poor initialization may produce a large amount of error. Therefore, this paper proposes a calibration method which can minimize measurement errors.

• Tribology and Lubricants
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• 제32권6호
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• pp.189-194
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• 2016

Wear debris in lubricating oil can be indicative of potential damage to mechanical parts in rotating and reciprocating machinery. Therefore, on-line or in-line monitoring of lubricating components in machinery is of great importance. This work presents a device based on inductive measurement of lubricating oil to detect magnetic wear particles in a tested volume. The circuit in the device consists of Maxwell Bridge and LVDT to measure inductance differences between pure and contaminated oil. The device detects the passage of ferrous particles by monitoring inductance change in a coil. The sensing principle is initially demonstrated at the microscale using a solenoid. The device is then tested using iron particles ranging from $50{\mu}m$ to $100{\mu}m$, which are often found in severely worn mechanical components. The test results show that the device is capable of detecting and distinguishing ferrous particles in lubricating oil. The design concept demonstrated here can be extended to an in-line monitoring device for real-time monitoring of ferrous debris particles. A simulation using the CST code is performed to better understand the inductive response in the presence of magnetic bodies in the oil. The CST simulation further verifies the effectiveness of inductance measurement for monitoring magnetic particles within a tube.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1941-1960
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• 2019

Unmanned aerial vehicles (UAVs), acting as mobile base stations (BSs), can be deployed in the typical fifth-generation mobile communications (5G) scenarios for the purpose of substantially enhancing the radio coverage. Meanwhile, UAV aided underlay device-to-device (D2D) communication mode can be activated for further improving the capacity of the 5G networks. However, this UAV aided D2D communication system is more vulnerable to eavesdropping attacks, resulting in security risks. In this paper, the D2D receivers work in full-duplex (FD) mode, which improves the security of the network by enabling these legitimate users to receive their useful information and transmit jamming signal to the eavesdropper simultaneously (with the same frequency band). The security communication under the UAV coverage is evaluated, showing that the system's (security) capacity can be substantially improved by taking advantage of the flexible radio coverage of UAVs. Furthermore, the closed-form expressions for the coverage probabilities are derived, showing that the cellular users (CUs)' secure coverage probability in downlink transmission is mainly impacted by the following three factors: its communication area, the relative position with UAV, and its eavesdroppers. In addition, it is observed that the D2D users or DUs' secure coverage probability is relevant to state of the UAV. The system's secure capacity can be substantially improved by adaptively changing the UAV's position as well as coverage.

• 센서학회지
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• 제28권1호
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• pp.52-57
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• 2019

Studies to augment emotion and immersion in multimedia content through olfactory stimulation are being increasingly conducted in the past two decades, and a variety of scent devices have been developed. Most of the scent devices are very large and heavy; consequently, they are installed on a table rather than being attached to the Head-mounted Display (HMD). Even if such devices are mounted on the HMD, it is not possible to control the scent density because of the size limitation, and it is not easy to be immersed in the experience because of the noise caused by the scent device. In order for an actual virtual reality or an augmented reality system to work efficiently with the scent device, three conditions - noiseless, a compact design, and concentration control- must be satisfied. In this study, we design a scent device that satisfies these three conditions. By using a miniature piezoelectric pump, a small size scent device is designed so that it can be easily attached to the lower end of the HMD, and hardly any noise is generated. Moreover, it is possible to control the concentration of the scent by controlling the piezoelectric pump using amplitude and frequency.