• Journal of Life Science
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• v.21 no.4
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• pp.549-553
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• 2011

This study was performed to determine whether or not urinary 1-hydroxypyrene (1-OHP) levels can be accurately detected by our 1-OHP-detecting $TiO_2$-Bead-HPLC assay that we developed based on the molecular imprinting method. Our method showed a variation coefficient of 4.97% and a between-day variation coefficient of 4.43%, suggesting that this may be a very stable method. In addition, the recovery rate of 1-OHP from a mixture of 1-OHP and similar substances using our $TiO_2$-Bead-HPLC method was estimated to be 105.6%. The correlation coefficient between the conventional enzyme-HPLC method and this new method was 0.74 (p<0.01) when the urine samples were tested. Based on this result, it is conceivable that our method could be a useful technique for measuring urinary 1-OHP levels. Moreover, our method has some advantages of being easier and less expensive than the conventional method. The results of this study suggest that our method can facilitate the development of a urine 1-OHP sensor using $TiO_2$-coating beads and that development of beads by molecular imprinting can be applied to analysis of chemicals other than 1-OHP.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.4
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• pp.327-338
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• 2014

The objective of this study is to enhance the effectiveness of Korean Inspection and Maintenance (I/M) program. Three main tasks are: to measure pollutant emissions of in-use light-duty diesel vehicles (LDVs); to evaluate the validity of existing smoke control scheme for low-smoke-emitting vehicles, which have diesel particulate filters, DPF, to meet stringent Euro-5 emission limits; and to assess the necessity and the benefit of $NO_x$ inspection, which is not involved in current I/M program. We measured second-by-second smoke, particulate and gaseous emissions of 27 LDVs using opacity smoke meter, photo-acoustic soot sensor, and portable emissions measurement system, respectively, under the Korean I/M test driving cycle, KD-147. We find that the DPF plays a key role in controlling soot, which can be considered as black carbon contained in particulate matter. Thus, from an I/M perspective, we believe smoke inspection strategies for Euro-5 diesel vehicles should be more focused on the capability of detecting DPF malfunctions or failures, in order to keep DPF properly functional. Fleet averaged distance-specific $NO_x$ emissions are consistently higher than corresponding emission limits, and the values are similar among pre-Euro-3, Euro-3, and Euro-4 vehicle fleets. These findings indicate that the $NO_x$ inspection should be incorporated into current I/M program in order to manage urban $NO_x$ emissions. This research allows the Korean I/M program keep pace with developments in vehicle technologies, as well as the increased emphasis on $NO_x$ with respect to air quality and human health.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.779-789
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• 2015

Because cable-supported bridges have long spans and large members, their movements and geometrical changes by temperatures tend to be bigger than those of small or medium-sized bridges. Therefore, it is important for maintenance engineers to monitor and assess the effect of temperature on the cable-supported bridges. To evaluate how much the superstructure expands or contracts when subjected to changes in temperature is the first step for the maintenance. Thermal movements of a cable-stayed bridge in service are evaluated by using long-term temperatures and displacements data. Displacements data are obtained from extensometers and newly installed GNSS (Global Navigation Satellite System) receivers on the bridge. Based on the statistical data such as air temperatures, each sensor's temperatures, average temperatures and effective temperatures, correlation analysis between temperatures and displacements has been performed. Average temperatures or effective temperatures are most suitable for the evaluation of thermal movements. From linear regression analysis between effective temperatures and displacements, the variation rate's of displacement to temperature have been calculated. From additional regression analysis between expansion length's and variation rate's of displacement to temperature, the thermal expansion coefficient and neutral point have been estimated. Comparing these parameters with theoretical and analytical results, a practical procedure for evaluating the real thermal behaviors of the cable-supported bridges is proposed.

• Journal of Sensor Science and Technology
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• v.12 no.1
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• pp.16-23
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• 2003

Thermoluminescent properties of $Li_2B_4O_7$ single crystal grown by Czochralski method have been investigated. The high quality $Li_2B_4O_7$ single crystal without core was obtained at rotation speed of 10 rpm for seed crystal and pulling speed below $0.18\;mm{\cdot}h^{-1}$. The structure of $Li_2B_4O_7$ single crystal was classified as tetragonal by XRD analysis. The TL glow curve was composed with three overlapped peaks which can be easily deconvoluted and the TL response of $Li_2B_4O_7$ single crystal TLD to X-ray radiation is linear within the range of $50\;mGy{\sim}1.5\;Gy$. Activation energies of three TL glow peaks analyzed by the various heating rates method and PL spectrum were 0.93, 1.78 and 2.25 eV, respectively.

• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.681-688
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• 2005

This study investigates an existing steel plate girder railroad bridge after superstructure rehabilitation to monitor static and dynamic responses using Fiber Bragg Grating (FBG) sensors. This paper also presents an experimental technique to estimate the vertical deflection of the bridge using FBG sensors. Seven FBG sensors are multiplexed in a single optical fiber and installed in parallel pairs along the length of the bridge, with one set at the top flange and the other at the bottom flange. In addition to FBG sensors, a conventional electric strain gauge and anLVDT are installed at the mid-span of the bridge for comparison. A test train consisting of one locomotive is placed at the center of the bridge to produce the maximum static effect. The train is also made to pass over the bridge at different speeds ranging from 10 km/h to 90 km/h to monitor the dynamic response of the bridge. This study demonstrates that the measured strains using the FBG sensor compared well with the readings from the electric strain gauge. The results show that the proposed instrumentation technique is capable of estimating the vertical deflection of the bridge for various loading conditions, which is crucial in structural health monitoring. Several dynamic characteristics of the bridge were also identified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.851-860
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• 2020

With an increase in the aging population and a rising social interest in health and welfare, studies to improve healthcare in the elderly are being actively conducted. This study attempted to improve the current design and manufacture of elevating electric wheelchairs to enhance user safety and convenience. Seat design based on the user's body shape, convenience while boarding or alighting, caster turning radius and, safety and stability features that prevent shaking when the user gets up or sits down were improved. A driving experiment was conducted to evaluate the operation of the indoor electric wheelchair designed and manufactured with these additional functionalities. During the test, the performance parameters evaluated were continuous driving time, turning radius, maximum lifting and lowering load, maximum lifting height, noise level, minimum distance sensing by the driving auxiliary sensor, ability to interact with server and app programs, and the duty cycle maximum error rate. The test confirmed that this improved electric wheelchair successfully met target parameters. In a future study, we will evaluate this improved electric wheelchair from a user's perspective for its usability parameters, such as satisfaction, convenience and stability.

• KIISE Transactions on Computing Practices
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• v.23 no.6
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• pp.371-378
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• 2017

In modern society, awareness of diabetes is growing with an increase in the elderly population and an increase in the incidence of diabetes. In particular, diabetic patients can suddenly develop hypoglycemic shock; therefore, it is important to measure blood glucose periodically. However, self-monitoring blood glucose meters are difficult to carry and it is difficult to manage the value. To solve these problems, the blood glucose measurement system has been developed as a sensor attached to the body or as one of the functions of smart devices, but it has not been commercialized. In this paper, we propose a smart band with a blood glucose measurement function. If a user enters a schedule to measure blood glucose level, such as before/after meals, in the app, he/she can receive a measurement alarm from the band. The user can measure the blood glucose level at any time using the band, and the measured value is transmitted and managed by the app including behavior history such as before/after meals and the time. This will help the user to manage, diagnose and prevent health problems. The system has been tested using two medical device-certified products, and each blood glucose measurement value has been confirmed to be more accurate.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.5
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• pp.28-34
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• 2008

The real-time biomedical signal monitoring is a very important factor to realize the ubiquitous healthcare environment. Most of these devices for monitoring the biomedical information get the PPG signal from the user, and these signals are utilized for monitoring their health. It is inconvenient to get the PPG because the user should wear the finger probe with his finger for measuring the PPG signal. Also it is difficult to get the PPG correctly, because of the motion artifacts from the movement of the user. In this paper, we develop the watch type biomedical signal monitoring system without the finger probe, and propose the new algorithm for reducing the motion artifacts from the PPG signal. We designed the system which gets the PPG from the sensor on the wrist band strip. As compared with the finger probe type, this system we proposed is more affected by the motion artifacts. So to filter this motion artifacts, we propose the new method; the improved PMAF(Periodic Moving Average Filter) method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1167-1174
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• 2009

In the monitoring of a patient in a sickroom, not only the physiologic and environmental data of the patient, which is automatically measured, but also the clinical data(clinical chart)of the patient, which is drew up by a doctor or nurse, are recognized as important data. However, since in the current environment of a sickroom, clinical data is collected being divided from the data that is automatically measured, the two data are used without an effective integration. This is because the integration of the two data is difficult due to their different collection times, which leads the reconstruction of clinical data to be remarkably uncertain. In order to solve these problems, a method to synchronize the continuous environmental data of a sickroom and clinical data is appearing as an important measure. In addition, the increase of use of small machines and the development of solutions based on wireless communications provide a communication platform to the developers of health care. Thus, this paper realizes a remote system for taking care of patients based on a web that uses mobile phones. That is, clinical data made by a nurse or doctor and the environmental data of a sick room comes to be collected by a collection module through a wireless sensor network. An observer can see clinical data and the environmental data of a sickroom through his/her mobile phone, integrating and storing his/her data into the database. Families of a patient can see clinical data made by hospital and the environment of the sick room of the patent through their computers or mobile phones outside the hospital. Through the system,hospital can provide better medical services to patients and their families.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.59-63
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• 2005

Respiration motion causes movement of internal structures in the thorax and abdomen, making accurate delivery of radiation therapy to tumors in those areas a challenge. Accounting for such motion during treatment, therefore, has the potential to reduce margins drawn around the clinical target volume (CTV), resulting in a lower dose to normal tissues (e.g., lung and liver) and thus a lower risk of treatment induced complications. Among the techniques that explicitly account for intrafraction motion are breath-hold, respiration gating, and 4D or tumor-tracking techniques. Respiration gating methods periodically turn the beam on when the patient's respiration signal is in a certain part of the respiratory cycle (generally end-inhale or end-exhale). These techniques require acquisition of some form of respiration motion signal (infrared reflective markers, spirometry, strain gauge, thermistor, video tracking of chest outlines and fluoroscopic tracking of implanted markers are some of the techniques employed to date), which is assumed to be correlated with internal anatomy motion. In preliminary study for the respiratory gating radiation therapy, we performed to measurement of this respiration motion signal. In order to measure the respiratory motion signals of patient, respiration measurement system (RMS) was composed with three sensor (spirometer, thermistor, and belt transducer), 4 channel data acquisition system and mobile computer. For two patients, we performed to evaluation of respiratory cycle and shape with RMS. We observed under this system that respiratory cycle is generally periodic but asymmetric, with the majority of time spent. As expected, RMS traced patient's respiration each other well and be easily handled for application.