• Journal of Sensor Science and Technology
• /
• v.3 no.3
• /
• pp.28-35
• /
• 1994

Caustic Soda Treatment Systems need a concentration measurement device in order to monitor the weight reduction amount of polyester fabrics. Since the reduction process requires several concentration measurements, we have to do the unit titration fast and exactly. Therefore, a proposition of estimation algorithm for finding the equivalent point in the titration process is needed. In this paper, we used the cardinal spline algorithm, to estimate the proper curve with the measured pH-values after each injection of titration sdution, to predict the equivalent point. While the processing time is elapsed, several equivalent points are estimated and drawed the line graph of fabrics weight reduction automatically. Finally, we designed the hardware and the software of an automatic titration system that can generate the reduction ending signal of Caustic Soda Treatment System.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.12B
• /
• pp.1236-1243
• /
• 2010

The perimeter defense system was created and its characteristics were evaluated. It was designed to utilize the fiber sensing device, namely OTDR(Optical Time Domain Reflectometer) which has been used for the maintenance of the optical communication network. An OTDR was constituted by a pulse laser with the nature of 1310nm, +15dBm for the observation of 400 meter optical fence. The high-speed 32-bit processor(S3C2440) has applied to MPU(Main Processor Unit) which helps to improve the performance of OTDR algorithms. Consequently, the maximum error was 0.84 meter on the performance test of the 10km monitoring and the pass criteria of ${\pm}1m$ satisfied in all the sections. The alarm delay time was under 3 sec after detecting the disorder. For the case of secondary trespassing after primary trespassing, the optical switch was installed in OTDR to monitor the secondary trespassing and to measure the multi-point detection. Therefore, this paper shows that the detections of secondary trespassing and multi-point is possible by means of optical switch.

• Restorative Dentistry and Endodontics
• /
• v.26 no.2
• /
• pp.134-140
• /
• 2001

The polymerization shrinkage of composite resins is an important drawback although the composites have many advantages-more esthetic and conservative than metallic restoratives etc. The purposes of this research were to develop a new measurement method and to manufacture an instrument that can measure the initial dynamic volumetric shrinkage of composite resins during polymerization. The instrument was basically an electromagnetic balance that constructed with a force transducer using position sensitive photo detector(PSPD) and a negative feedback servo amplifier of proportional-derivative(PD) controller. The volumetric change of composites during polymerization was detected continuously as buoyancy change in distilled water by means of Archimedes's principle. It was converted to continuous electrical voltage signal in real time. The signal was properly conditioned and filtered and then it was stored in computer by a data acquisition(DAQ) board. By using this electronic instrument. the dynamic patterns of the polymerization shrinkage of eight commercial(Z-100, DenFil, AeliteFil, Z-250, P-60, SureFil, Synergy compact, and Tetric ceram) composite resins were measured and compared. The results were as follows. 1. From this project of developing instrument, the ability has been achieved that can acquire and process data of electrical signal transformed from various physical phenomenon by using temperature, displacement. photo. and force transducer. As a consequence, the instrumentation and measurement system used to analyze the physical characteristics of various dental materials in dental research field can be designed, manufactured and implemented in lab. 2. This instrument has some advantages. It was insensible to temperature change and could measure true dynamic volumetric shrinkage in real time without complicated process. It showed accuracy and high precision results with small standard deviation. 3. The polymerization shrinkage of composites was significantly different between brands and ranged from 2.47％ to 3.89％, The order of polymerization shrinkage was as follows, in order of increasing shrinkage, SureFil, P60, Z250, Z100, Synergy compact. DenFil, Tetric ceram, and AeliteFil. 4. The polymerization shrinkage rate per unit time, dVol％/dt, showed that the instrument can provide an indirect research method for polymerization reaction kinetics.

• Journal of Ocean Engineering and Technology
• /
• v.29 no.2
• /
• pp.169-174
• /
• 2015

This paper addresses experimental methodologies to measure the temperature-dependent thermal conductivity of the insulation materials popularly used for LNG cargo containment systems. The measurement techniques considered in this paper are the guarded hot plate (GHP) method and heat flow method (HFM). The former is based on the power supplied to the hot plate to keep the temperature constant, and the latter is based on a direct heat flux measurement. In order to improve the accuracy of the HFM, the thermal conductivity obtained by GHP was cross-compared with the HFM results, and a calibration factor was derived. It was found that the thermal conductivities measured by the two methods corresponded well under room temperature, but the deviation tended to slightly increase as the temperature decreased. Because of the easy installation and operability of HFM, it can be used to measure thermal conductivity in a large scale mock-up test or unit insulation panel test, where the GHP method is difficult to apply.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.23 no.3
• /
• pp.294-301
• /
• 2020

Man-In-Simulant Test(MIST) provides a test method to evaluate chemical protective equipments such as protective garments, gloves, footwear and gas mask. The MIST chamber is built to control concentration of chemical vapor that has a activity space for two persons. Non-toxic methyl-salicylate(MeS) is used to simulate chemical agent vapor. We carried out to measure inward leakage MeS vapors by using passive adsorbent dosimeter(PAD) which are placed on the skin at specific locations of the body while man is activity according to the standard procedure in MIST chamber. But more time is required for PADs and there is concern of contamination in PADs by recovering after experiment. Therefore detector for measuring in real time is necessary. In order to analyze in real time the contamination of the personal protective equipment inside the chemical environment, we have developed a wireless real-time gas detector. The detector consists of 8 gas-sensors and 1 control-board. The control-board includes a CPU for processing a signal, a power supply unit for biasing the sensor and Bluetooth-chipset for transmission of signals to external PC. All signals from gas-sensors are converted into digital signals simultaneously in the control-board. These digital signals are stored in external PC via Bluetooth wireless communication. The experiment is performed by using protective equipment worn on manikin. The detector is mounted inside protective equipment which is capable of providing a real-time monitoring inward leakage MeS vapor. Developed detector is demonstrated the feasibility as real-time detector for MIST.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.3
• /
• pp.700-712
• /
• 2011

Due to recently advanced electrical devices, human can access computer network regardless of working location or time restriction. However, currently widely used mouse, joystick, and trackball input system are not easy to carry and they bound user hands exclusively within working space. Those make user inconvenient in Ubiquitous environments.. In this paper, we propose multiple dimension human motion detection system based on wireless sensor networks. It is a portable input device and provides easy installation process and unbinds user hands during input processing stages. Our implemented system is comprised of three components. One is input unit that senses user motions and transmits collected data to receiver. Second is receiver that conveys the received data to application, which runs on server computer. Third is application that performs command operations according to received data. Experiments shows that proposed system accurately detect the characteristics of user arm motions and fully support corresponding input requests.

• Journal of the Ergonomics Society of Korea
• /
• v.33 no.1
• /
• pp.59-68
• /
• 2014

Objective: The aim of this study is to investigate the effect of BackJoy on how it effectively reduces the physical load generated in a posture in which the user sits, increases user's comfort and satisfaction, and maintains the correct posture. Background: Because of development of science and economic development, most office workers and students spend about 75% of their working time in chairs. However most of them have a poor posture. Method: This experiment conducted measurement using a pressure mat and surveyed to evaluate fatigue level, satisfaction and comfort of sit. The study is experimented 20 male and 14 female participants. The participants carried out four different types of tasks and each task took 20 minutes long. Results: In the case of experiment results before and after the use of BackJoy, average pressure, contact area and pressure per unit area appear to prove that using BackJoy is more effective. Conclusion: Through this study, the BackJoy's effects for the maintenance of good posture and loads that occur in the body are reduced. In the future study, there are some researches needed for various verifications using an EMG sensor that shows loads of vertebrae and we need to analyze each group of the participants by dividing them. Application: The evaluation method used in this study can be applied to evaluating ergonomic chairs.

• Structural Monitoring and Maintenance
• /
• v.2 no.4
• /
• pp.319-338
• /
• 2015

The electro-mechanical impedance (EMI) technique makes use of surface-bonded lead zirconate titanate (PZT) patches as impedance transducers measuring impedance variations monitored on host structural components. The present experimental work further evaluate an alternative to the conventional EMI technique which performs measurements of the variations in the output voltage of PZT transducers rather than computing electromechanical impedance (or admittance) itself. This paper further evaluates a variant of the EMI approach presented in a previous work of the present authors, suitable, for low-cost concrete structures monitoring applications making use of a credit card-sized Raspberry Pi single board computer as core hardware unit. This monitoring approach is also deployed by introducing a new damage identification index based on the ratio between the area of the 2-D error ellipse of specific probability of EMI-based measurements containment over that of the 2-D error circle of equivalent probability. Experimental results of damages occurring in concrete cubic and beam specimens are investigated under increasing loading conditions. Results illustrate that the proposed technique is an efficient approach for identification and early detection of damage in concrete structures.

• Proceedings of the SAREK Conference
• /
• 2007.11a
• /
• pp.606-611
• /
• 2007

Pulsation is an inherent phenomenon in reciprocating compressors. It interacts with piping to cause vibrations and performance problems. Indiscriminately connecting to a compressor can be dangerous and cost money in the form of broken equipment and piping, poor performance, inaccurate metering, unwanted vibration, and sometimes noise. Piping connected to a compressor can materially affect the performance and response. To minimize these detrimental effects, reciprocating compressor system should be equipped by pulsation suppression system. This study discusses pressure pulsation phenomena occurred in a reciprocating compressor system. An experiment applied air compressor unit, as pulsating pressure generator, has been done. The compressor was connected sequentially to a snubber model and pressure tank. Sensor probes were placed on the inlet and outlet pipes of snubber. Compressor was driven by a motor controlled by a frequency regulator. The experiment was conducted by adjusting the regulator at 40Hz. General information about an internal gas flow can be achieved by numerical analysis approach. Information of the velocity, pressure and turbulence kinetic energy distribution are presented in this paper. Based on this result, the design improvement might be done.

• Journal of the Korea Society for Simulation
• /
• v.25 no.1
• /
• pp.35-43
• /
• 2016

Increasing the proportion of an embedded system in automotive industry, test methods for evaluation and fault detection of the embedded system have been researched. HILS is a test method that is used in the development and test of complex real-time embedded systems. In this study, we defined the HILS method of the ECU, one of the embedded systems used in automobiles. Our method is to create a test model that can provide a virtual vehicle environment to the ECU on the basis of the actual vehicle data. The test model has reference information that can transmit the sensor signal and CAN Message into the ECU from HILS tester. In this study, the HILS can detect faults of the target ECU.