• Smart Structures and Systems
• /
• v.31 no.3
• /
• pp.301-309
• /
• 2023

Tilt is a key indicator of structural safety. Real-time monitoring of tilt responses helps to evaluate structural condition, enable cost-effective maintenance, and enhance lifetime resilience. This paper presents a prototype wireless sensing system for structural tilt measurement. Long range (LoRa) technology is adopted by the sensing system to offer long-range wireless communication with low power consumption. The sensor integrates a gyroscope and an accelerometer as the sensing module. Although tilt can be estimated from the gyroscope or the accelerometer measurements, these estimates suffer from either drift issue or high noise. To address this challenging issue and obtain more reliable tilt results, two sensor fusion algorithms, the complementary filter and the Kalman filter, are investigated to fully exploit the advantages of both gyroscope and accelerometer measurements. Numerical simulation is carried out to validate and compare the sensor fusion algorithms. Laboratory experiment is conducted on a simply supported beam under moving vehicle load to further investigate the performance of the proposed wireless tilt sensing system.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.404-408
• /
• 2009

Gas pipelines in bridges, roads and subway construction sections can undergo abrupt stress and vibration changes. To protect human life from any gas leakage accidents induced by the abrupt stress and vibration, the gas pipeline system needs to be continuously monitored. The estimation method of pipeline stress using MEMS wireless tilt sensor has been developed and its validity has been evaluated using a lab test bench.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.3
• /
• pp.116-124
• /
• 2011

In this study, a new method to estimate the bridge deflection is developed by using Wireless Tilt Sensor. Most of evaluations of structural integrity, it is very important to measure the geometric profile, which is a major factor representing the global behavior of civil structure, especially bridges. In the past, Because of the lack of appropriate methods to measure the deflection curve of bridges on site, the measurement of deflection had been done restrictly within just a few discrete points along the bridge. Also the measurement point could be limited to locations installed with displacement transducers. So, in this study, the deflection of the structure was measured by wireless tilt sensor instead of LVDT(Linear Variable Differential Transformer). Angle change of tilt sensor shows structural behavior by the change of the resistor values which is presented to voltage. Moreover, the maximum deflection was calculated by changing the deflection angle which was calculated as V(measured voltage) ${\times}$F(factor) to deflection. The experimental tests were carried out to verify the developed deflection estimation techniques. Because the base of tilt measuring is the gravity, uniform measurement is possible independent of a measuring point. Also, measuring values were showed very high accuracy.

• The Journal of Korea Robotics Society
• /
• v.5 no.4
• /
• pp.294-301
• /
• 2010

In order to produce a convenient robot for the aged and the lower limb disabled, it is needed for the research detecting implicit walking intention and controlling robot by a user's intention. In this study, we developed sensor module system to control the walking- assist robot using FSR sensor and tilt sensor, and analyzed the signals being acquired from two sensors. The sensor module system consisted of the assist device control unit, communication unit by wire/wireless, information collection unit, information operation unit, and information processing PC which handles integrated processing of assist device control. The FSR sensors attached user's the palm and the soles of foot are sensing force/pressure signals from these areas and are used for detecting the walking intention and states. The tilt sensor acquires roll and pitch signal from area of vertebrae lumbales and reflects the pose of the upper limb. We could recognize the more detailed user's walking intention such as 'start walking', 'start of right or left foot forward', and 'stop walking' by the combination of FSR and tilt signals can recognize.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.01a
• /
• pp.742-745
• /
• 2009

This paper proposes a wireless LAN antenna system that tracks an object automatically by using image-based tracking. The proposed system consists of a camera and a pan-tilt unit in addition to a directional wireless LAN antenna. The camera and the directional antenna are set in same direction and they are set on the pan-tilt unit. A target object which has a wireless LAN receiver is tracked by using images captured by the camera. And the directional antenna faces in same direction as the camera by the pan-tilt unit. Therefore, the directional antenna keeps pointing the receiver, and a transmitting efficiency is improved. A result of a fundamental experiment shows that a receiver attached to a flying airship was tracked by a prototype of the proposed antenna system. The airship flied about, and the proposed antenna system was set on a roof of a building. The experimental result indicates an effectiveness of the proposed system compared to the conventional directional LAN antenna.

• 한국정보통신설비학회:학술대회논문집
• /
• 2007.08a
• /
• pp.191-195
• /
• 2007

Recently, landslides frequently happen at a natural slope during period of intensive rainfall. With rapidly increasing population of steep terrain in Korea, landslides have become one of the most significant natural hazards. Thus, it is necessary to protect people from landslides and to minimize the damage of houses, roads and other facilities. To accomplish this goal, many landslide prediction methods have been developed in the world. In this study, a simple landslide prediction system that enables people to escape the endangered area is developed. The system is focused to debris flows which happen frequently during periods of intensive rainfall at steep slopes in Kangwondo. This system is based on the wireless sensor network that is composed of sensor nodes, gateway, and server system. Sensor nodes that are composed of sensing part and communication part are newly developed to detect sensitive ground movement. Sensing part is designed to measure tilt angle and acceleration accurately, and communication part is deployed with Bluetooth (IEEE 802.15. I) module to transmit the data to the gateway. To verify the feasibility of this landslide prediction system, a series of laboratory tests is performed at a small-scale earth slope supplying rainfall by artificial rainfall dropping device. It is found that sensing nodes installed at slope can detect the ground motion when the slope failure starts. It is expected that the landslide prediction system by wireless senor network can provide early warnings when landslides such as debris flow occurs, and can be applied to ubiquitous computing city (U-City) that is characterized by disaster free.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.2
• /
• pp.135-141
• /
• 2011

A smart home provides services that its inhabitant needs or wants, by integrating and simultaneously controlling various devices and sensors. In this study, we focused on a smart-home system for people with disabilities and for elderly people. We introduced a new type of system for real-time analysis of body posture of the inhabitants of a smart home. The system includes the concept that offers remote healthcare or medical services by using a 3D tilt sensor for recognizing the static and dynamic postures of inhabitants in real time. It consists of a smart-home server and a 3D tilt sensor, and it uses wireless technology to communicate with the inhabitants and thus enhance their mobility. The smart-home server includes the inference engine that differentiates the dynamic postures from the static ones. Finally, we also demonstrate the usefulness of the proposed system by applying it to a real environment.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.8
• /
• pp.918-931
• /
• 2013

The conventional object tracking techniques using PTZ camera detects object movements by analyzing acquired image. However, this technique requires expensive hardware devices to perform a complex image processing. And it is occasionally hard to detect object movements, if an acquired image is low quality or image acquisition is impossible. In this paper, we proposes a smart security CCTV system applying to wireless sensor network technique based on IEEE 802.15.4 standard to overcome the problems of conventional object tracking technique, which enables to track suspicious objects by detecting object movements and GPS data in sensor node. This system enables an efficient control of PTZ camera to observe a wide area, decreasing image processing complexity. Also, wireless sensor network is implemented using mesh networks to increase the efficiency of installing sensor node.

• Journal of The Korean Society of Integrative Medicine
• /
• v.8 no.2
• /
• pp.1-9
• /
• 2020

Purpose : The aim of this study was to compare the effects of the abdominal draw-in exercise (ADIE) and the dead bug exercise (DBE) on the pelvic anterior tilt angle and the activities of the gluteus maximus (GM), erector spinae (ES), and semi tendinosus (ST) during prone hip extension. Methods : A total of 22 female adults with weak abdominal muscles were divided into two groups: ADIE group (n=11) and DBE group (n=11). The muscle activities of the GM, ES, and ST along with the pelvic anterior tilt angle during prone hip extension were measured using a wireless surface electromyograph and gyro sensor before performing the prescribed exercise. Two groups conducted the assigned exercise for 10 minutes. After the exercise, their muscle activities and the pelvic anterior tilt angle were equally re measured. Results : In the DBE group, the muscle activity of GM was significantly increased after the intervention (p<0.05). However, there was no significant difference between the two groups in the amount of increase in the activity of GM (p>0.05). Moreover, in both groups, the activity of ES and the pelvic anterior tilt angle decreased significantly after the intervention (p<0.05) The decreased quantity in the pelvic anterior tilt angle and in the activity of ES showed no difference between the two groups (p>0.05). In the activity of ST, there was no significant difference within and between the two groups (p>0.05). Conclusion : Therefore, we suggest that ADIE and DBE are effective for women with weak abdominal muscles since the ES activity and pelvic anterior tilt angle are reduced during prone hip extension.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2011.05b
• /
• pp.49-52
• /
• 2011

This study concerned with the retention structures or inverted temporary building for displacement measurement in the underground soil after drilling a vertical tilt sensor attached to the vertical distance required to maintain a real-time measurement and management in order to install the wireless measuring devices installed in the field through remote control and management program for the safety of retaining structures temporary building be found on the internet in real time temporary building the retention is to develop a safety management system. And based on this technology to monitor the future status of the various structures possible to add a variety of sensors and Life Cycle Prediction of the structure and needs to evolve into intelligent systems and wireless networks using wireless communications infrastructure systems based on expanding domestic market penetration by developing instrumentation pioneer in overseas markets as well as the activation can also be judged.