• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1371-1383
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• 2022

In this study, the amount of coal waste dump was calculated using six Digital Elevation Models (DEMs) produced between 2006 and 2018 in Jangseong-dong, Taebaek-si, Gangwon-do, and the subsidence was observed by applying the Persistent Scatterer Interferometric SAR (PSInSAR) technique on the Sentinel-1 SAR images. As a result of depositing activities using DEMs, a total of 1,668,980 m³ of coal waste was deposited over a period of about 12 years from 2006 to 2018. The observed subsidence rate from PSInSAR was -32.3 mm/yr and -40.2 mm/yr from the ascending and descending orbits, respectively. As the thickness of the waste pile increased, the rate of subsidence increased, and the more recent the completion of the deposit, the faster the subsidence tended to occur. The subsidence rates from the ascending and descending orbits were converted to vertical and horizontal east-west components, and 22 random reference points were set to compare the subsidence rate, the waste rock thickness, and the time of depositing completion. As a result, the subsidence rate of the reference point tended to increase as the thickness of the waste became thicker, similar to the PSInSAR results in relation to the waste thickness. On the other hand, there was no clear correlation between the completion time of the deposits and the rate Of subsidence at the reference points. This is because the time of completion of the deposits at all but 5 of the 22 reference points was too biased in 2010 and the correlation analysis was meaningless. As in this study, the use of DEM and PSInSAR is expected to be an effective alternative to compensate for the lack of field data in the safety management of coal waste deposits.

• Fire Science and Engineering
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• v.30 no.1
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• pp.138-148
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• 2016

A firefighting simulation was developed in order to assess the physical work capacity of firefighters. The simulation consisted of eight common firefighting tasks, including walking with radiant heat for 3 min while wearing full personal protective equipment (PPE). Nine professional firefighters performed the test a total of three times with a 5 min rest interval between each session. The entire series of tests took approximately 30 min to complete ($381{\pm}30s$). Rectal temperatures were found to increase from $37.4{\pm}0.3^{\circ}C$ to $38.5{\pm}0.4^{\circ}C$, while heart rates were found to increase from $92{\pm}18bpm$ to $185{\pm}13bpm$ during testing. Time to completion of the test drills and non-modified physical fitness values showed a significantly negative correlation (r = -0.728, p < 0.05). Firefighters who had longer periods of firefighting service had longer duration time and also recorded higher scores using an integrated scoring system of time to completion (TTC) and physiological strain index (PhSI). The results indicated that the determination of TTC alone can be a misrepresentation of capability, as it neglects to account for accumulated heat strain. The simulated firefighting test provided a useful insight into physical fitness level, but also the comprehensive work capacity of the firefighters when assessed based on TTC and PhSI.

• Journal of the HCI Society of Korea
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• v.11 no.1
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• pp.21-28
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• 2016

This study investigated the usefulness of the wraparound function that are usually employed in information displays of list types within diverse digital devices. The wraparound function indicates the cursor movement jumping to the last/first item when users move up/down the cursor at the first/last item in a list. This study performed two experiments on different kinds and lengths of lists with or without the wraparound function. The experimental results showed that the usefulness of the wraparound depended on the kinds and lengths of the list. In a long list, the wraparound helped to reduce the number of cursor movements, but made the moving speed of the cursor slow. The reason why the moving speed became slow might be because the participants needed the time to decide cognitively on whether they did the wraparound or not. In a more longer list, the increased time required for the decision making could be complemented by the decreased time owing to the reduced number of cursor movements with the effectiveness of the wraparound, thereby reducing total task completion time. Moreover, the participants admitted that the wraparound became more strongly necessary in the case of more long lists.

• The Journal of Korean Physical Therapy
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• v.29 no.4
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• pp.175-180
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• 2017

Purpose: This study examined the effects of fast walking training on a treadmill on the spinal alignment and muscle thickness of normal adults. Methods: A total of 36 college students in their twenties participated in the study for eight weeks, and they were divided into the normal walking, fast walking, and speed change groups. All the groups were measured in a pre-test before training. The subjects performed exercise three times per week for six weeks. A post-test was conducted six weeks after training began, and a follow-up test was done two weeks after the training ended.Trunk and pelvic tilts were measured in Formetric 4D for the spinal alignment of the subjects. The muscle thickness was examined in the trunk with an ultrasound test. Repeated-measures ANOVA was conducted to test the main effects and interactions among the measurement variables according to time and group. Results: Significant differences were observed in the pelvic tilt according to time. There were significant differences in the external oblique, internal oblique, transverse abdominal muscle according to time. The post-test results showed significant differences in the left external oblique, internal oblique muscles between before training, six weeks into training, and two weeks after the completion of training. There were significant interactions in the left oblique muscles according to the time and group. Conclusion: These findings have some value for patient rehabilitation and clinical applications and interventions through walking training.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1177-1184
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• 2011

Gas-to-Solid (GTS) technology is composed of three stages: hydrate production, transportation, and regasification. For efficient operation of regasification plants, it is crucial to predict the temperature and flow rate of hot water necessary to dissociate the hydrate pellets. Dissociated gas escaping from the pellet surface, when in contact with hot water, will alter the flow field and consequently alter the heat transfer rate. Methane hydrate pellet dissociation characteristics in low- to moderatetemperature water were investigated by taking images of the changes in the hydrate pellets' shapes in a pressurized reactor and measuring the total time required for complete melting of the pellets. The effects of water temperature, hydrate conversion rate, and flow speed on the dissociation completion time were also investigated. Bubbling gas released from the pellet surface induced a secondary flow that enhanced the heat transfer rate and thus decreased the dissociation time. It was also found that a considerable flow rate was needed to significantly decrease the dissociation time.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.255-260
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• 2008

The purposes of this study were to determine the actual state of the indoor air quality by TVOC concentration and residents' responses and to analyze the influencing factors of IAQ in newly built university dormitory. The field measurements on the levels of TVOC and HCHO were carried out three times at an interval of 4 weeks in 3 rooms of a dormitory. The questionnaire survey on the residents that inquired into the lifestyle, the consciousness related to IAQ, and the responses of SHS was fulfilled. According to the results, the level of TVOC was approximately $0.14{\sim}18.5ppm$ and HCHO was $0.23{\sim}6.89ppm$ during 3 month since construction completion, which are seriously in excess of standard level, and seemed to be on the decrease as time goes by. The factors influencing the differences of the levels of TVOC or HCHO were the amount of ventilation including infiltration, heating temperature, relative humidity, or the use of living things including chemical. However, the residents rarely felt the responses of SHS and did not be conscious of the importance of ventilation.

• Journal of the Korean housing association
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• v.20 no.6
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• pp.135-143
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• 2009

The purposes of this study were to determine the actual state of the indoor air quality by measuring TVOC Concentration and surveying residents' responses in a newly built university dormitory and to analyze the influencing factors of IAQ. Field measurements on the concentrations of TVOC and HCHO were carried out three times at 4 week intervals in 3 rooms of a dormitory. A questionnaire survey was conducted on residents which inquired into the resident's lifestyle, their consciousness of IAQ, and the responses to SHS. According to the results, TVOC concentrations were 0.14~18.5 ppm and HCHO concentrations were 0.23~6.89 ppm during the 3 months following the completion of construction, showing a serious state in which standard levels are exceeded, though these levels seemed to decrease over time. The factors influencing the differences in the levels of TVOC and HCHO were the ventilation volume including infiltration, the heating temperature, relative humidity, or the use of living matter that include chemical ingredients. However, the residents rarely felt the symptoms of SHS and were not conscious of the importance of ventilation.

• Journal of Korean Academy of Nursing
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• v.30 no.5
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• pp.1347-1356
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• 2000

The present study is a descriptive study to investigate nurses’perception of barriers to research utilization. A total of 274 participants in this study consisted of registered nurses working in a large, urban and academic medical center. A questionnaire packet containing the Barriers Scale, and a demographic profile was distributed to nurses and they were asked to return the packet to a return-box in the Nursing Office after completion. The greatest barrier was insufficient time on the job to implement new ideas. Next was ‘implications for practice are not made clear'. Also the item of the English language in research articles was considered to be the ninth barrier. The greatest mean score of each of the sub-scales was the communication factor. The were followed by the organization, research, and nurse factors. Compared with the means from other studies, the mean scores of the communication and research factors were higher in this study. Nurses who had not taken a class of research methods found the communication and research factors as a higher barrier than those who did. Also, nurses who did not participate in a conference last year perceived the research factor as higher than those who did. It is recommended that English and research classes should be strengthened in educational nursing programs. The researchers should also describe the section of implication for practice as more detail and clearer for the understanding of nurses; Lastly journals in a libraries or online journal systems should be easily accessible.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3619-3637
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• 2022

Big data analytics offers endless opportunities for operational enhancement by extracting valuable insights from complex voluminous data. Hadoop is a comprehensive technological suite which offers solutions for the large scale storage and computing needs of Big data. The performance of Hadoop is closely tied with its configuration settings which depends on the cluster capacity and the application profile. Since Hadoop has over 190 configuration parameters, tuning them to gain optimal application performance is a daunting challenge. Our approach is to extract a subset of impactful parameters from which the performance enhancing sub-optimal configuration is then narrowed down. This paper presents a statistical model to analyze the significance of the effect of Hadoop parameters on a variety of performance metrics. Our model decomposes the total observed performance variation and ascribes them to the main parameters, their interaction effects and noise factors. The method clearly segregates impactful parameters from the rest. The configuration setting determined by our methodology has reduced the Job completion time by 22%, resource utilization in terms of memory and CPU by 15% and 12% respectively, the number of killed Maps by 50% and Disk spillage by 23%. The proposed technique can be leveraged to ease the configuration tuning task of any Hadoop cluster despite the differences in the underlying infrastructure and the application running on it.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.191-196
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• 1981

In order to utilize the Koryangju distillers' grain for the acetic acid fermentation, the extracting methods and effects of the extracts on the fermentations were investigated. The result obtained are as follows. 1. Cold extracting method by which the distillers grain is extracted with 3 times of water for 60 hours at room temperature was better than hot extracting method in terms of the fermentation rate and the quality of vinegar product. 2. Optimum conditions and some results of surface fermentation based on the medium added by the extracts are as follows, optimum amount of the extracts to be added to the medium is 20-30% of total media; acetic acid production rate at log phase was 0.16g/100$m\ell$, hr.; recovery was 91.17%; and the time of 40 hours was required for the completion of fermentation. 3. Organoleptic quality of the vinegar which is produced by adding the extracts was superior to two commercial products examined.