• Journal of Sensor Science and Technology
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• v.19 no.1
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• pp.8-16
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• 2010

This research proposes measuring of BCG(ballistocardiogram) to monitor heart activities in a non-constrained environment, at home or work. Unlike with ECG, measuring BCG does not require the attachment of leads on the subject's body and allows signal measuring in a non-constrained state. It enables effective long-term monitoring of cardiac conditions. In this study a chair type BCG measurement system to continuous monitor the activity of the heart is implemented. The instrument consists of upper petal and ready for press of chair load cell sensor is attached to measure the change of the object's weight. In order to extract the output ballistic signal from the weight and force sensor signals. Beside the signal processing circuit for the digital conversion, the ballistic signal is detected using DAQ equipment. Signal processing algorithm including wavelet transforms for noise cancellation, template matching for normalization and peak detection in BCG is developed. ECG and BCG were concurrently measured to evaluate the performance of the system, and comparing the characteristics of the two signals verified the possibility of the system in non-constrained and nonconscious health monitoring.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2006.06a
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• pp.97-100
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• 2006

A sensor and measuring system were implemented to measure both uroflow and urophonography signal during urination for diagnose the BPH(benign prostatic hypertrophy). The implemented system was composed of the uroflow sensor using the load-cell, the urophonography measurement sensor so as stethoscope type, pre-processing part for sensors signal detection, amplifier and filter, system control parts and PC measurement program. A simulator of the lower urinary system that is experimental equipment implemented for evaluates the developed system. The two signals were measured using implemented system and analyzed these signal by means of time domain and frequency domain for extraction of the characteristic parameter which can most effectively reflected by the occlusion of the lower urinary system. Furthermore two signals were measured and analyzed with the subject of 5 healthy adult for clinical application possibility of the implemented system. As a result, the most influence bandwidth of effect according to occlusion of the lower urinary system is $253{\sim}282Hz$ of the urophonography signal.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.4 s.235
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• pp.563-569
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• 2005

This paper develops a finite element model of a cabover type large truck. The finite element model is for evaluating torsional stiffness of the frame of the large truck. The torsional test of the frame is conducted in order to validate the developed finite element model. A load cell is used to measure the load applied to the frame. An angle sensor is used to measure the torsional angle. An actuator is used to apply a load to the frame. A vertical upward load and a vertical downward load are applied to the frame in the torsional test. The frame's torsional stiffness is computed with the measured load and torsional angle in the torsional test. The finite element model of the large truck includes cab, deck and payload, suspension, and tire. Cab, deck, and suspension are modeled not to affect the frame's torsional stiffness. The simulation is performed with the developed finite element model for evaluating the frame's torsional stiffness. The simulation results show a very good correlation with the torsional test results in the tendency of changing of the frame's torsional stiffness not only with the direction of the applying load but also with the amount of the applying load. In addition, the simulation results predict the measured torsional stiffness of the frame with about $5{\%}$ error.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.731-737
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• 2005

This paper evaluates dynamic performance of a cab over type large-sized truck for estimating the effects of frame's torsional characteristics using a computer model. The computer model considers two mounting methods of frame, flange mounting and web mounting. Frame is modeled by finite elements using MSC/NASTRAN In order to consider the flexibility of frame. The torsional test of the frame is conducted In order to validate the modeled finite element model. A load cell is used to measure the load applied to the frame. An angle sensor is used to measure the torsional angle. An actuator is used to apply a load to the frame. To estimate the effects of frame's torsional characteristics on dynamic performance, simulations are performed with the flange mounting and web mounting frame. Simulation results show that the web mounting frame's variations of roll angle, lateral acceleration, and yaw rate are larger than the flange mounting frame's variations, especially in the high velocity and the second part of the double lane course.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.754-761
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• 2008

In general, stress measurement of existent shotcrete lining be used by pressure cells. but, measuring instrument is lost by high pressure at shotcrete lining construction and pressure cell's measurement value have to low believability by natural conditions like curing temperature. In this study, proposed techniques to measure without utilizing sensitive stress sensor in natural condition at point that want stress of shotcrete lining after shotcrete lining construction. Executed numerical analysis to forecast stress level that interact in tunnel shotcrete lining, measured strain of hole by load action through hole in shotcrete lining. 3D FEM(finite element method) is enforced through various parameters curing time of shotcrete lining, thickness, load condition. Different model cases applied by parametic study. As analysis result, it could grasp development possibility of method that propose this time because it could examine corelation with strain by near hole of shotcrete lining and stress about load condition.

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.1-8
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• 2016

Current indoor intrusion detection and location tracking methods have the weakness in seamless operations in tracking the objective because the object must possess a communicating device and the limitation of the single cell size (approximate $100cm{\times}100cm$) exits. Also, the utilization of CCTV technologies show the shortcomings in tracking when the object disappear the area where the CCTV is not installed or illumination is not enough for capturing the scene (e.g. where the context-awarded system is not installed or low illumination presents). Therefore, in this paper we present an improved in-door tracking system based on sensor networks. Such system is built on a simulated scenario and enables us to detect and extend the area of surveillance as well as actively responding the emergency situation. Through simulated studies, we have demonstrated that the proposed system is capable of supplementing the shortcomings of signal cutting, and of estimating the location of the moving object. We expect the study will improve the better analysis of the intruder behavior, the more effective prevention and flexible response to various emergency situations.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.135-139
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• 2007

Recently Data Centric Storage (DCS) schemes are variously studied for several applications (e.g. natural environment investigation, military application systems and environmental changes monitoring). In DCS scheme, data is stored at nodes within the network by name. There are several drawbacks in the existing schemes. The first is the inefficiency of the range query processing on not considered the locality of store point. the second is the non-homogeneity of store load of each sensors in case of the sensor distribution density is non-uniformed. In this paper, we propose a novel data centric storage scheme with the sensor distribution density which satisfied with the locality of data store location. This scheme divides whole sensor network area using grid and distributes the density bit map witch consist of the sensor density information of each cell. sensors use the density bit map for storing and searching the data. We evaluate our scheme with existing schemes. As a result, we show improved load balancing and more efficient range query processing than existing schemes in environment which sensors are distributed non-uniform.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.6
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• pp.566-571
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• 2010

EPS (Electric Power Steering) is important device for improving vehicle's dynamics and static performances. This paper deals with simulator design for C-EPS (Colum type-EPS), development assist and returnability control algorithm. First, C-EPS system model was simply designed because EPS system is complex control system that has many unknown variables. These parameters were simplified through assumptions. Second, C-EPS simulator was designed for development of control algorithm. This simulator has SAS (Steering Angle Sensor), dual torque sensor, dual load cell for measuring rack force, dual linear actuator for generating tire force and Data Acquisition System. Using this simulator, control methods ware tested. Third, control algorithm was designed for torque assist and returnability. Assist torque map and returnability torque map were found by lots of simulation test. These torque maps were tuned for EPS actuator control. The simulation result was compared with non-EPS system result. In this research, the C-EPS simulator was designed for development of control algorithm about torque assistant and returnability. Using this simulator, control algorithm was improved.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.161-166
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• 2012

Intravenous (IV) injection is widely used to supply Ringer solution directly into a vein in hospital. Generally, a passive injection method has been used, which causes the inconsistent flow rate of fluid and inappropriate control of injection time by a patient. It leads to an unnecessary nurse's overwork and decrement of IV injection's effect. To solve these problems, flow control infusion pumps have been developed. But because of relatively heavy weight and high price, its usage has been limited. In the present study, a new automatic IV injection system is developed. It is installed with a small pressing mechanism driven by a small electric motor to regulate the flow rate by pressing tube. Proportional integral derivative (PID) feedback control algorithm is applied to control the electric motor. The system is smaller in size and uses lower power than the existing commercial product. The newly developed system is also installed with networking capability, which enables monitoring the status of several automatic IV injection system at the same time.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.491-492
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• 2021

현대사회의 물류 현장에서 근로자가 직접 물류를 분류하는 작업을 하거나 상하차 작업을 진행하고 있다. 본 논문에서 제안하는 자율주행 로봇을 이용한 물류 분류 시스템은 물류 운반 로봇과 컨베이어 벨트로 구성된다. 물류 운반 로봇은 경로 설정 및 장애물 감지가 가능한 자율주행 기능을 가지며, 컨베이어 벨트는 하차된 물류의 무게 측정과 배송 가격을 표시하는 기능을 가진다. 본 연구의 결과는 근로자들의 노동 강도와 육체적 또는 정신적인 피해로 인해 발생하는 산업재해의 발생률을 감소시킬 수 있는 기대와 심야 시간에 부족한 인력을 보충하여 24시간 물류센터를 가동할 수 있는 가능성을 가진다.