• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.115-123
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• 2018

In a long-span bridge, the cables are important elements that support the load of the bridge. Accordingly, the cable tension is a very important variable in evaluating the health and safety of the bridge. The most popular methods of estimating the cable tensions are the direct method, which directly measures the cable stresses using load cells, hydraulic jacking devices, etc., and the vibration method, which inverses the tensions using the cable shapes and the measured dynamic characteristics. Studies on the use of the electromagnetic (EM) sensor, which detects the magnetic field variations caused by the change in the stress of the steel in the cable, are increasing. In this study, the lift-off test, the EM sensor, and the vibration method (Vision-based System and Accelerometer) were used to measure cable tension, and their results were compared and analyzed.

• Korean Journal of Applied Biomechanics
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• v.30 no.2
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• pp.155-163
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• 2020

Objective: This study to identify the mechanism of head impact that occurs during youth soccer game with regard to head injuries in sports. Method: Ten male subjects (age: 10.0±2.0 yrs.) were participated during 10 soccer practices spread out over a time period of 10 weeks. During each soccer game, the participants agreed and wore the X-Patch (wireless accelerometer, gyroscopes). The X-Patch records the head impact mechanics, such as peak linear acceleration (PLA), peak rotational acceleration (PRA), peak rotational velocity (PRV), Head Injury Criterion (HIC), and the location of impact. Results: A total of 501 impacts to the head were measured over the 10 soccer games, PLA 17.8±10.4 g, PRA 3168±2442 rad/s²; PRV 16.1±10.6 rad/s; HIC 11.7±34.2. The severity of impact was classified into 3 ranges; low 10~39 g (482 impacts); medium 40~69 g (17 impacts); and high >69 g (2 impacts). There are no significant differences in PLA and HIC (p=0.08, p=0.15), however PRA and PRV show the differences (p<.05) between each of the participants. For the analysis comparing between the soccer games, there are no significant differences in PLA, PRA, PRV and HIC (p=0.11, p=0.13, p=0.14, p=0.05). Conclusion: Our results indicated that there were significant differences between athletes, especially in terms of rotational acceleration, whereas there were significant differences in linear and rotational based variable between each of the soccer games. Although the vast majority of impacts were below 39 g there were 2 potentially dangerous impacts above 69 g. It is important that future research continuous to measure head impact mechanics during soccer to help understand head injury mechanisms to ensure the safety of athletes.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.26 no.2
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• pp.78-87
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• 2013

Objectives : This work aimed to review clinical trial trend of Korean medicine's face rejuvenation and suggest future trial using embedded needle(Maesun) based on Evidence-based medicine's PICO Model. Methods : 46 papers were searched from Oasis and DBPia, then 8 papers were engaged in review of clinical trial trend. Based on PICO model, clinical trial's patient, intervention, and outcome measurement were suggested. Results : Evidence level of clinical trials is relatively low, because their study designs are almost case report or case series. No study have comparison groups. Outcome measurement is varied, however, 3D face scanner were used to measure before-after changes of face. Based on review, we suggested that necessity of intervention standardization, measuring of normal control group and 2D/3D combined outcome measurement of face. Conclusions : There are many demands for revealing efficacy and safety of Korean medicine's intervention, also for face rejuvenation using embedded needle. For meeting the level of demands, more rigorous works are needed.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.2
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• pp.73-80
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• 2013

Due to the fact that possible risk associated with soil-crop-food chain transfer, metal contamination in croplands has become a major topic of wide concern. Accumulation of toxic metals in edible parts of crops grown in contaminated soils has been reported from number of crops including rice, soybean, wheat, maize, and vegetables. Therefore, in order to ensure food safety, measures are needed to be taken in mitigating metal pollution and subsequent uptake by crop plants. Present paper critically reviewed some of the cost effective remediation techniques used in minimizing metal uptake by crops grown in contaminated soils. Liming with different materials such as limestone ($CaCO_3$), burnt lime (CaO), slaked lime [$Ca(OH)_2$], dolomite [$CaMg(CO_3)_2$], and slag ($CaSiO_3$) has been widely used because they could elevate soil pH rendering metals less-bioavailable for plant uptake. Zn fertilization, use of organic amendments, crop rotation and water management are among the other techniques successfully employed in reducing metal uptake by crop plants. However, irrespectively the mitigating measure used, heterogeneous accumulation of metals in different crop species is often reported. The inconsistency might be attributed to the genetic makeup of the crops for selective uptake, their morphological characteristics, position of edible parts on the plants in respect of their distance from roots, crop management practices, the season and to the soil characteristics. However, a sound conclusion in this regard can only be made when more scientific evidence is available on case-specific researches, in particular from long-term field trials which included risks and benefits analysis also for various remediation practices.

• Tunnel and Underground Space
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• v.21 no.1
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• pp.1-10
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• 2011

In these days, the development of optical fiber sensor technology is so remarkable that it can measure various physical and chemical quantities ranging from a few millimeters to over several kilometers. In addition, it is attempted to assess the structural integrity of the state of the advanced technologies and existing structures such as ships, aircrafts, and bridges. This paper introduced the case histories of the measuring technology of optical fiber applied on structures such as roads and tunnels. The case history using OTDR (Optical Time Domain Reflectometery) was also introduced in this paper. Measurement of the pre-convergence of a tunnel is essential to assess the safety of a tunnel and understand the geological conditions ahead of an advancing tunnel. Therefore, the pre-convergence measuring technology using OTDR is expected to substitute conventional measuring techniques.

• Tunnel and Underground Space
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• v.18 no.2
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• pp.125-133
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• 2008

The rock treatment methods for improving bearing capacity and reducing settlement of the underground roadway structure foundation on fractured rock was studied in this paper. Also, effective reinforcement scheme was evaluated by numerical analysis for the application to the practical construction. Various in-situ and laboratory tests were executed systematically at Yeongi-goon, Ohoongchungnam-do, Korea, for the purpose of defining the physical and mechanical properties of rock. Consequently the effective treatment methods insuring the bearing capacity of fractured rock were proposed. In addition, the adequate reinforcing depth of the comparatives measure, such as double rod, triple rod injection methods and micropile, were investigated from the case study. Finally, the most effective construction scheme with the consideration of safety and economical aspects were proposed by using numerical analysis(Plaxis ver. 8.2).

• Fire Science and Engineering
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• v.31 no.4
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• pp.52-58
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• 2017

This study investigated the pressure difference distribution and the flow characteristics among room, ancillary room, and stair case by carrying out the numerical simulations on the air flow inside the pressurized air supply smoke control system. Numerical simulations were conducted to analyze pressure and velocity distribution of compartments by pressurized air supply for the air-leakage test facility which was built to measure the effective leakage area. In this study, the leakage of air was considered by locating the narrow slit onto fire door and window of room. Simulated results using this method precisely followed the previous experimental results for the pressure differences between the stair case and ancillary room. Predicted results showed that the local leakage of air rarely affected the overall flow pattern and pressure distribution. Although the average velocity over the door between room and ancillary room satisfied the regulation for fire safety, it was certified the unsafe outflow to ancillary room could be occurred in the local position such as the upper part of the door.

• Journal of Radiation Industry
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• v.11 no.1
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• pp.19-25
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• 2017

It is suggested that the dose limit recommended in the Enforcement Decree of Korea's Nuclear Safety Act should not exceed 150 mSv per year for radiation workers. Recently, however, ICRP 118 report has suggested that the threshold dose of the lens should be reduced to 0.2~0.5 Gy and the mean dose should not exceed 50 mSv per year for an average of 20 mSv over 5 years. Based on these contents, $^{123}I$, $^{99m}Tc$, and $^{18}F-FDG$, which are radioisotope drugs that are used directly by radiation workers in the nuclear medicine department in Korea are expected to receive a large dose of radiation in the lens in distribution and injection jobs to administer them to patients. The ED3 Active Extremity Dosimeter was used to measure the dose of the lens in the nuclear medicine and radiation workers and how much of the dose was received per 1 mCi.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.355-359
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• 2019

Schirmer test is one of the most used methods for the diagnosis of dry eye. We attempted to develop a tear level measurement tool to replace unreliable Schirmer test with inaccurate results. Absorbency tests for various absorbents were carried out. As a result, ${\alpha}$ cellulose pulp was selected as the absorbent. Prototypes were produced and evaluated twice. Finally a tear level measurement tool in the form of a strip of ${\alpha}$ cellulose pulp adhered to a polyurethane was prepared. Usability evaluation of prepared tear level measurement tool was performed. As a result, it was confirmed that it has a significant correlation with SM tube developed oversea recently. In addition, it was judged to be useful as an alternative to the Schirmer test in terms of measurement time and accuracy.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.631-640
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• 2009

The highest priority of the cruise trip is the safety and comfort of its passengers. Though the cruise lines take every appropriate measure to ensure that their Passengers are safe and experience enjoyable vacations it is hard to fulfill all passenger's personnel requirement with limited number of crews. Generally, each passenger is issued an identification card which contains their digital photo and personal identification information on a magnetic strip that he or she must present when entering or leaving the ship. This technology allows the ship to know which Passengers and crew members are on board and which are not. However, this system has some limitations of functions and usage. To support each passenger as his or her personal liking, additional number of crews or some kind of new system is needed. In this paper, the crew support system based on sensor network using wireless and wired communication technologies was studied. To design the system, PLC(Power Line Communication) system and ZigBee based passenger location recognition, classification system has studied experimentally. By using this system, crews can serve passengers more closely and personally with less effort.