• Radiation Oncology Journal
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• v.36 no.2
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• pp.139-146
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• 2018

Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3%, 3%-5%, 5%-10%, and >10% were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.89-99
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• 2006

The study were to assess technical factors between the high score group and the low score group, from the subjects of 16 male national gymnasts, and to analyze the kinematical characteristic and main technical cause on technique of Akopian's 3D motion analysis of the male vaulting game in 2001 classification championship. The result of this study is this. There were not so much difference between the two groups in term; of the time of board contact, pre-flight, and total performance, but it takes shorter time when the players who are in the high point group take down the board, and they take long time for post-flight(p<.01). The high point group has a longer perpendicular distance in the moment of horse taking off, 0.05m on the average, than the low point group. The high point group shows 0.16m higher on the average than the other group in term; of the height of post-flight(p<.01). In the phase of board contact, the range of horizontal velocity at board take on were $7.66m/s{\sim}7.33m/s$, but there weren't significantly statistic differences between two groups. The hight score group were 0.68m/s faster than the low point group at the horizontal velocity at board take off event(<.05). About the average horizontal velocity of deceleration, AG1(-1.95m/s) reduces the speed more than AG2(-1.57m/s)(p<.05). And the hight score group were 0.37m/s faster than the low point group at the vertical velocity at horse take off event(<.05). When board taking off, the projectile angle of com were $38.7{\sim}37.8degree$ on the average. the comparative groups show almost same results. When horse taking off, the HPVy of the high point group were 37.6 degree which were a little higher than the low point group. The angular velocities of the players who takes on the horse with a right hand and then takes off with a left hand in the high point group were 14.97rad/sec, 10.82rad/sec in the low point group. However, the angular velocity of the players who takes on the horse with a left hand and then takes off on a right hand with the high point group were 14.97rad/sec, 15.56rad/sec in the low point group.

• Fire Science and Engineering
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• v.24 no.4
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• pp.62-68
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• 2010

The present study purposed to develop the water mist package system for the cultural properties fire prevention and fire suppression system through analyzing fire protection system and cultural property's characteristic, and to suggest directions for the development of cultural property fire prevention system in the future. Maximum safety with minimum damage has issued a main objective in fire protection of the cultural property in Korea. Two types of the water mist nozzles having a low pressure had been developed by KEI. The one is for inside using in wooden cultural properties, the flow rate is 30~35 l/min and the discharging pressure is 13~14 bar. The other one is for out-side of wooden properties, the flow rate is 25~30 l/min and the discharging pressure is 14~15 bar. To evaluate the nozzles performance test, we made the fire scenario and full-scale model of wooden cultural properties for fire test. The size of full-scale model was 4.9 m length, 4 m wide, 6.6 m height, all was made by wooden. This real fire test results showed that the low pressure water mist nozzles having a $200{\mu}m$ dour size were very effectively fire extinguishing and suppression on wooden cultural properties fire. Even though the oil fuel fire was not extinguished, the fire suppression effects for the during mobilization of fire brigade was enough.

• Membrane Journal
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• v.17 no.4
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• pp.318-328
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• 2007

This study was carried out to evaluate the performance of the separate membrane (HF; hollow fiber membrane with polysulfone) process applied with the external membrane types, internal pressure membrane types and external-internal types according to the variations of pressure and membrane pore size in the purification treatment process of the lake water. The maximum permeate flux was average values of 282 LMH and 234 LMH with the pore size of 0.3 and 0.05 ${\mu}m$ respectively in the external pressure membrane process, and 443 LMH and 522 LMH with the pore size of 0.3 and $0.05{\mu}m$ respectively in the internal pressure membrane process. In addition, the maximum permeate flux of the process that was applied with external and internal membrane pressure simultaneously showed the average values of 674 LMH with the pore size of $0.3{\mu}m$, and 648 LMH with the pore size of $0.05{\mu}m$. Therefore, maximum yield per unit area is supposed when the separate membrane that was applied with external and internal pressure simultaneously are used to treat the lake water.

• Journal of Biomedical Engineering Research
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• v.34 no.1
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• pp.8-13
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• 2013

Persons with sensorineural hearing impairment have troubles in hearing at noisy environments because of their deteriorated hearing levels and low-spectral resolution of the auditory system and therefore, they use hearing aids to compensate weakened hearing abilities. Various algorithms for hearing loss compensation and environmental noise reduction have been implemented in the hearing aid; however, the performance of these algorithms vary in accordance with external sound situations and therefore, it is important to tune the operation of the hearing aid appropriately in accordance with a wide variety of sound situations. In this study, a sound classification algorithm that can be applied to the hearing aid was suggested. The proposed algorithm can classify the different types of speech situations into four categories: 1) speech-only, 2) noise-only, 3) speech-in-noise, and 4) music-only. The proposed classification algorithm consists of two sub-parts: a feature extractor and a speech situation classifier. The former extracts seven characteristic features - short time energy and zero crossing rate in the time domain; spectral centroid, spectral flux and spectral roll-off in the frequency domain; mel frequency cepstral coefficients and power values of mel bands - from the recent input signals of two microphones, and the latter classifies the current speech situation. The experimental results showed that the proposed algorithm could classify the kinds of speech situations with an accuracy of over 94.4%. Based on these results, we believe that the proposed algorithm can be applied to the hearing aid to improve speech intelligibility in noisy environments.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.321-334
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• 2017

Process surveillance within agricultural biogas plants (BGPs) was concurrently studied by high-throughput 16S rRNA gene amplicon sequencing and an optimized quantitative microscopic fingerprinting (QMF) technique. In contrast to 16S rRNA gene amplicons, digitalized microscopy is a rapid and cost-effective method that facilitates enumeration and morphological differentiation of the most significant groups of methanogens regarding their shape and characteristic autofluorescent factor 420. Moreover, the fluorescence signal mirrors cell vitality. In this study, four different BGPs were investigated. The results indicated stable process performance in the mesophilic BGPs and in the thermophilic reactor. Bacterial subcommunity characterization revealed significant differences between the four BGPs. Most remarkably, the genera Defluviitoga and Halocella dominated the thermophilic bacterial subcommunity, whereas members of another taxon, Syntrophaceticus, were found to be abundant in the mesophilic BGP. The domain Archaea was dominated by the genus Methanoculleus in all four BGPs, followed by Methanosaeta in BGP1 and BGP3. In contrast, Methanothermobacter members were highly abundant in the thermophilic BGP4. Furthermore, a high consistency between the sequencing approach and the QMF method was shown, especially for the thermophilic BGP. The differences elucidated that using this biphasic approach for mesophilic BGPs provided novel insights regarding disaggregated single cells of Methanosarcina and Methanosaeta species. Both dominated the archaeal subcommunity and replaced coccoid Methanoculleus members belonging to the same group of Methanomicrobiales that have been frequently observed in similar BGPs. This work demonstrates that combining QMF and 16S rRNA gene amplicon sequencing is a complementary strategy to describe archaeal community structures within biogas processes.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.862-869
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• 2010

Numerical analysis was done to evaluate the gas flow distribution in small scale SCR system which has $2.4{\times}2.4{\times}3.1\;m^3$ in volume and 25,300 Sm3/hr in flue gas flow capacity. Various types of baffles proposed for controlling the flow uniformity were evaluated by the CFD analysis to find the optimal geometry of the baffle in the SCR system. By installing baffles in the SCR system, the RMS (%) value was raised up to 6.2% compared with the baffle-uninstalled state. The effect of baffle thicknesses on the RMS (%) value was not shown within 0 and 8 mm in thickness, but the RMS (%) value was raised by 2.5% in 10 mm of baffles thickness, which causes the unstability in flow. By comparison between the shape of baffles, it is known that the lattice type baffle has better performance in controlling the flow uniformity than the circular truncated cone type baffle or mixer type baffle. RMS (%) values have more that 10% difference according to the shape of baffle type.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.218-224
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• 2012

Recently, as the needs of developing the micro autonomous underwater vehicle (AUV) are increasing, the acquisition of the elementary technology is urgent. While they mostly utilizes information of the forward looking sonar (FLS) in conventional studies of the local path control as an elementary technology, it is desirable to use the obstacle avoidance sonar (OAS) because the size of the FLS is not suitable for the micro AUV. In brief, the local path control system based on the OAS for the micro AUV operates with the following problems: the OAS offers low bearing resolution and local range information, it requires the system that has reduced power consumption to extend the mission execution time, and it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent local path control algorithm based on the beam modeling of OAS with the evolution strategy (ES) and the fuzzy logic controller (FLC), is proposed. To verify the performance and analyze the characteristic of the proposed algorithm, the course control of the underwater flight vehicle (UFV) is performed in the horizontal plane. Simulation results show that the feasibility of real application and the necessity of additional work in the proposed algorithm.

• Korean Business Review
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• v.19 no.2
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• pp.23-46
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• 2006

In modern economic societies, individuals are governed by organizations and they managed their daily lives in one way or another. through such organizations. All activities of the organizations are carried out by the job performance of individuals. Job is a very important factor for both individuals and organizations. The study is the explore. the effect of job characteristics and organizational characteristics on the job satisfaction in the small- and medium- sized firms in Namdong und Banwool Area. Job characteristics and organizational justice were hypothesized to be positively related to job satisfaction. To examine the influence of job characteristics and organizational justice on job satisfactions, data were collected from 320 employees of the small- and medium- sized manufacturing companies in Namdong und Banwool Area. This research took independent variables as the core job characteristics of the job characteristic theory such as skill variety, job stagnation, job importance, autonomy, feed back, and organizational justice as distributive and procedural justice. As a result, I can make the following suggestions. First, The Results show that job characteristics and organizational justice were significant and important predictors of job satisfaction. Secondarily, to raise the job desire of organizational members, job must be designed in such a way that the members can highly recognize their job characteristics.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.6
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• pp.42-48
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• 2002

The design, construction and performance test of a convenient multi-purpose irradiator is described. A multi-purpose irradiator using Cesium-137 has been developed for studies of low dose radiation effects in biology and for calibration of Thermo Luminescent dosimeter(TLD). During the operation, three rods of radioactive material which are 10cm in length revolve 180 degrees and irradiate biological samples, or TLD, and return to their shielded position, after the programmed time. A programmable Logic Controller(PLC) controls the sequence of operation, interlock, motor rotation and safety system. The rotation speed of biological samples can vary up to 20 RPM. A real time monitoring system was also incorporated to check and control the operation status of the irradiator. The capacity of the irradiation chamber was 4.5 liters. The isodose distribution at arbitrary vertical planes was measured by using film dosimetry. The dose-rate was 0.13 cGy/min in air and 0.11 cGy/min in water equivalent material in the case of Cesium-137. Range of activity was 2 Ci. The homogeneity of dose distribution in the chamber was ${\pm}$7%. The actual radiation level on the surface was within permissible levels. The irradiator had a maximum 0.35 mR/min radiation leakage on its surface.