• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.135-138
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• 2004

Conventional piezoelectric lead-zirconate-titanate (PZT) senor has high sensitivity, but it is very brittle. Recently polymer films such as polyvinylidene fluoride (PVDF) and poly(vinylidene fluoride­trifluoroethylene) (P(VDF-TrFE)) copolymer have been used as a sensor. The advantages of polymer sensor are the flexibility and mechanical toughness. Simple process and possible several shapes are also additional advantages. Polymer sensor can be directly embedded in a structure. In this study, nondestructive damage sensitivity of single basalt fiber/epoxy composites was investigated with sensor type and thermal damage using AE and oscilloscope. And AE waveform for epoxy matrix with various damage types was compared to each other. The damage sensitivity of two polymer sensors was rather lower than that of PZT sensor. The damage sensitivity of PVDF sensor did not decrease until thermal damage temperature at $80^{\circ}C$ and they decreased significantly at $110^{\circ}C$ However, the damage sensitivity of P(VDF-TrFE) sensor at $110^{\circ}C$ was almost same in no damage sensor. For both top and side impacts, the difference in arrival time increased with increasing internal and surface damage density of epoxy matrix.

• Journal of Korean Neurosurgical Society
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• v.62 no.2
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• pp.243-255
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• 2019

Objective : Although traumatic brain injury (TBI) occurs in people of all age groups, the elderly population is at a particular risk. The proportion of elderly population in the society is markedly increasing and Korea is one of the most rapidly aging societies. Here, we analyzed the data from 904 patients older over 65 years who were registered in the Korean Neuro-Trauma Data Bank System (KNTDBS). Methods : The Korean Society of Neurotraumatology recorded data from 20 institutions between September 2010 and March 2014. This retrospective study examined the clinical epidemiology, sex difference, outcome epidemiology, sociodemographic variables, and outcomes in the geriatric population related to TBI based on data from the KNTDBS. Results : The study included 540 men and 364 women. The age distributions in the male and female groups were statistically significantly different. The most common cause of trauma was a fall and diagnosis was acute subdural hematoma. The incidence was the highest in men aged 80-84 years and in women aged 75-79 years. The most common time of arrival to hospital after TBI was within 1 hour and 119 rescue team provided first aid earliest to patients with TBI. The mortality rate stratified according to the cause of trauma was significantly different, with mortality rates of 3.77% in fall and 11.65% in traffic accident. The mortality rates according the severity of brain injury, Glasgow Coma Scale score, and treatment were statistically significant. Conclusion : To our knowledge, this study is the first to focus on elderly patients with TBI in Korea and particularly investigate mortality and characteristics related to TBI-related death based on data from the KNTDBS. Although the study has some limitations, our results may be used to obtain useful information to study targeted prevention and more effective treatment options for older TBI patients and establish novel treatment guidelines and health polish for the geriatric population.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.117-130
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• 1989

In this study, an implicit one-dimensional model, DWRM(Dynamic Wave Routing Model) was developed by using the four-point weighted difference method. By applying the developed model to the Keum River, the parameters were calibrated and the model applicability was tested through the comparison between observed and computed water levels. In addition, the effects of the construction of an estuary dam to the flood wave were estimated as a result of the model application. The results of the study can be summarized as follows; 1. The roughness coefficients were evaluated by comparison between observed and computed water level at Jindu, Gyuam and Ganggyeung station in 1985. The Root Mean Squares for water level differences between observed and computed values were 0.10, 0.11, 0. 29m and the differences of peak flood levels were 0.07, 0.02, 0. 07m at each station. Since the evaluated roughness coefficients were within the range of 0.029-0.041 showing the realistic value for the general condition of rivers, it can be concluded that the calibration has been completed. 2. By the application of model using the calibrated roughness coefficients, the R. M. S. for water level differences were 0.16, 0.24, 0. 24m and the differences of peak flood level were 0.17, 0.13,0.08 m at each station. The arrival time of peak flood at each station and the stage-discharge relationship at Gongju station agreed well with the observed values. Therefore, it was concluded that the model could be applied to the Keum River. 3. The model was applied under conditions before and after the construction of the estuary dam. The 50-year frequency flood which had 7, 800m$^3$/sec of peak flood was used as the upstream condition, and the spring tide and the neap tide were used as the downstream condition. As the results of the application, no change of the peak flood level was showed in the upper reaches of 19.2km upstream from the estuary dam. For areas near 9.6km upstream from the estuary dam, the change of the peak flood level under the condition before and after the construction was 0. 2m. However considering the assumptions for the boundary conditions of downstream, the change of peak flood level would be decreased.

• The Korean Journal of Pain
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• v.8 no.2
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• pp.251-256
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• 1995

Opioids produce strong analgesic effect result with some side effects such as nausea, vomiting, urinary retention, somnolence, and respiratory depression. Nalbuphine, an agonist-antagonist has, at low doses, an analgesic potency comparable to morphine with little side effects. Analgesic effect after continuous infusion of fentanyl-ketorolac-droperidol, or $Nubain^{(R)}$-ketorolac-dropertiodl combination in Cesarean section patients were assessed by numerical rating scale (NRS) and Prince Hednry scale (PHS). The patients were divided into two groups. Each group consists of 30 patients. Group 1 received 20 ${\mu}g$ of fentanyl the end of surgery. And then continuously infused with additional 380${\mu}g$ of fentanyl plus 120 mg of ketorolac and 2.5 mg of droperidol. Group 2 initially received 2 mg of $Nubain^{(R)}$ at the end of surgery and the remaining dose of $Nubain^{(R)}$ 38 mg plus ketorolac 120 mg and droperidol 2.5 mg was continuously infused. With all patients, initial dose of drug was administered by bolus of i.v. injection and the remaining dose was administered via i.v. using a Baxter Two $Infusor^{(R)}$. Pain scores and side effects were recorded at the time of recovery room arrival, and at interval of 30 min, 1 hr, 6 hr, 14 hr, 24 hr, 48 hr after start of continuous infusion. No significant difference was found between the pain scores and side effects of both groups although pain control effect was excellent in both groups. We concluded that $Nubain^{(R)}$ could be an alternative to fentanyl for postoperative pain control.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.161-173
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• 2020

This study analyzed local imbalances in the supply and demand of emergency medical services in Busan using the 119 emergency activity reports of the Busan Fire & Disaster Headquarters. The data for EMS activity reports in 2017 was converted into Jimgyegu units. The spatial distribution of the indicators representing the local imbalance of emergency demand and supply (number of reports, number of reports relative to the population, average coefficient of variation and outlier of on-site arrival time, and number of dispatches outside the jurisdiction) was analyzed using Hotspot analysis of GIS spatial statistics analysis. As a result of the analysis, the hot spot area and the cold spot area where both supply and demand of emergency services are concentrated were clearly distinguished. This means that the supply and demand of emergency services in Busan are locally unbalanced. In particular, there was a difference in the demand and supply of emergency services in the original downtown and its surrounding areas, and in the outskirts of Busan.

• Journal of Technology Innovation
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• v.13 no.2
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• pp.97-131
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• 2005

This paper has discussed several issues regarding the barriers and opportunities for technological catch-up by the late-comer countries and firms. As one of the barriers to technological catch-up, the paper emphasizes the uncertainty involved with the third stage of learning how to design. The barriers arise because as the forerunner firms refuse to sell or give license to successful catching-up firms who thus have to design the product by themselves. The paper discusses how to overcome this barrier. It also notes that if the crisis of design technology is a push factor for leapfrogging, arrival of new techno-economic paradigm can serve as a pull factor for leapfrogging, serving as a winder of opportunity. The, it emphasized the two risks with leapfrogging, namely the risk of choosing right technology or standards and the risk of creating initial markets, and how to overcome these risks. It discusses how to overcome these risks in leapfrogging, and differentiates diverse forms of knowledge accesses. Then, the paper takes up the issue of whether there can be a single common or several models for catch-up. A common element of catching-up is to enter new markets segments quickly, to manufacture with high levels of engineering excellence, and to be first-to-market by means of the best integrative designs. This observation is supported by the fact that Korea and Taiwan has achieved higher levels of technological capabilities in such sectors as featured by short cycle time of technology. The possibility of two alternative models for catch-up is also discussed in terms of the key difference between Korean and Taiwan, especially in the position toward the source of foreign knowledge and the paths taken toward the final goal of OBM. Taiwan followed the sequential steps of OEM, ODM and OBN, in collaboration or integration with the MNCs. Korean chaebols jumped from OEM directly to OBM even without consolidating design technology.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.1025-1031
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• 2007

GPS is widely used for positioning applications and attitude of a vehicle can be found also with multiple antennas. However, extremely weak signal level prevents GPS from indoor operation. DR with accelerometers and gyros and landmark based localization method used for indoor applications increase complexity and cost. In this paper, a simple but very efficient ultrasound based attitude determination system which determines both position and attitude in WSN is given. The range between transmitter and receivers are measured using the arrival time difference between ultrasound and RF signal. The 3 dimensional positions can be found using more than 3 range measurements. Furthermore, if more than 2 transmitters are used, the attitude can be determined using the baseline vectors obtained by differencing transmitter and receiver positions. The prototype system is implemented to evaluate the performance of the proposed method. In addition, an error analysis shows the relation between the attitude error and basel me length, quality of measurement and orientation of a vehicle. The static and dynamic experiments performed by micro mobile robot shows accurate position with less than 1.5cm error and attitude with less than 1 degree error can be obtained continuously with 20cm baseline. It is expected that these results can be adapted without modification to indoor applications such as home cleaning robot and autonomous wheelchair maneuvering.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.222-231
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• 2006

Deoxynivalenol (DON)-contaminated barley was treated with 0.1 M $Na_2CO_3$ solution to reduce DON content. DON content of barley was reduced from 2.08 to 0.67 ppm. Bread was made with 10, 20, and 30% DON-reduced barley flour added to white wheat flour. Farinogram showed water absorption and arrival time increased, while stability and mechanical tolerance index decreased when DON-reduced barley flour was added to white wheat flour. Gelatinization temperature, temperature at maximum viscosity, and maximum viscosity increased in amylogram with increasing addition of DON-reduced barley flour. Loaf volume of bread decreased with increasing amount of DON-reduced barley flour, while loaf weight increased. Barley flour pH increased by treatment with$Na_2CO_3$, and pH reduction decreased fermentation rate of yeast. Volume and size of gluten matrix decreased and crumb hardened in bread made with DON-reduced barley flour. Acceptabilities for color and texture were low in bread made with DON-reduced barley flour. Addition of DON-reduced barley flour at 30% reduced overall acceptability, whereas no significant difference in overall acceptability was observed when DON-reduced barley flour was added at 10 and 20%.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.255-260
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• 2017

In Korea, traffic accidents between pedestrians and vehicles in 2015 account for 38.8% of all accidents. This study proposes a system design that can measure the risk of conflict between a vehicle and a pedestrian. Firstly the systemdetect and estimate the position, speed, and directional data of the vehicle and the pedestrian. And then it estimate the conflict point between a vehicle and a pedestrian. The risk of conflict is quantified by estimating the pedestrian safety margin (PSM), which is the time difference between the arrival of the pedestrian at the crossing point to the point of conflict and the vehicle approaching the point. In this system each data is acquired through an external monitoring based evaluation module and an individual wearing module. In the future, such a system can be used for decision making such as the design of road hazard improvement facilities and the designation of the elderly protection area.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.421-435
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• 1998

An empirical formula for estimating duration magnitude(MD)is determined by analyzing 619 epicentral distance-duration data set, obtained from earthquakes of 1989-1998 recorded at the KMA network. Based on two assumptions: 1) observed signal duration decreases with increasing epicentral distance, and 2) seismographs of KMA are set at low-gain and therefore inclusion of sensitivity correction term in the equation is not necessary, scaling predicted duration at epicenter to Tsuboi's local magnitude yielded the duration magnitude equation: MD =2.0292$\times$log$\tau$＋0.00123Δ-1.4017 for 1/0$\leq$ML$\leq$5.0, where $\tau$is total signal duration(sec)and Δis epicentral distance(km). Event by event comparison of ML values against MD estimates for t152 events shows that for events having a same ML the difference in MD estimates reaches as high as 1.1 magnitude units. So, to test the usefulness of the duration magnitude equation, we have calculated ML-MD relations by which duration magnitude estimates are converted to local magnitudes ("predicted" ML, say) which are then compared with the directly determined local magnitude values. Except for events with stations where duration is anomalously reestimates(predicted ML) which are in an agreement within a 0.2 magnitude units with the corresponding ML values. Although this study could gain some insights into magnitudes of the past events, we still need to re-examine all the observables in order to obtain more reliable and precise information about magnitude and hypocenter location. So we will pursue a new local-magnitude scaling, as well as refinement of the duration magnitude equation, starting soon with re-reading the amplitudes-arrival time records of (and hence relocating) 250+earthquakes of 1979-present recorded at the KMA network. Thus, with more reliable and precise earthquake parameters determined we would better understand the recent seismicity and related tectonic process within and adjacent region to the Korean peninsula.peninsula.