• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.28-35
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• 2016

The in-situ thermal response test for the design of a ground heat exchanger of geothermal heat pumps have difficulty in predicting the outlet temperature according to the variation of conditions due to the expense and time. This paper suggests a 3-D CFD analysis method to predict the heat transfer performance of vertical type ground heat exchanger, which is mostly used in national, and the outlet temperature and the slope of two in-situ thermal response tests were compared to test the proposed CFD reliability. The results of CFD analysis showed that the outlet temperature was predicted to within $0.5^{\circ}C$ of the actual value and the slope was predicted to within 1.6%. The reliability of the CFD analysis method was confirmed using this process, and the outlet temperature prediction of the two in-situ thermal response tests was obtained by changing ${\pm}20%$ of the flow rate and the effective thermal conductivity conditions, respectively. The results of CFD analysis showed that the outlet temperature of Case 1 was 28.0 (-20%) and $29.6^{\circ}C$ (+20%) for the flow rate variation and $29.6^{\circ}C$ (-20%) and $28.0^{\circ}C$ (+20%) for the effective thermal conductivity variation, and the outlet temperature of Case 2 was 28.4 (-20%) and $29.8^{\circ}C$ (+20%) for the flow rate variation and $29.7^{\circ}C$(-20%) and $28.4^{\circ}C$(+20%) for the effective thermal conductivity variation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5477-5485
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• 2011

This study comparatively analyzed the instrumentation and the voicing structure, which were shown in the film music titled "Star Wars-Main Title" by John Williams(1932~), with analytical technique that the writer mapped out, and aimed to discover the progression principle in orchestration based on the results. Also, it applied a functional part-division method that was classified and distributed into 3 functional parts according to auditory cognitive level as for each of functional elements such as the musical element. And, it made it pattern for the vertical structure and the voicing structure in musical instruments, which were distributed to each functional part based on this, and comparatively analyzed the standard point in a change which were shown according to progression of music, namely, the operating technique. As for the results of this study, first, each theme has specific instrumentation pattern. Unity was emphasized by consistently organizing those things in exposition, reprise, and recapitulation of each theme. To reinforce diversity, an attempt was made such as adding and reducing auxiliary instruments in the middle part and the rear part. Second, even in a change of instrumentation pattern by passage in accordance with a change in theme amid each part, the same instrumental group was organized in the middle part, thereby having maintained unity. Third, to strengthen diversity by clause, which is forming each theme, a continuous change in voicing pattern was created by adding or omitting a part. Fourth, the voicing concentration was maintained the structure of "thinness-thickness" in the whole musical piece. However, in part 2 that is repeated theme 3, diversity was pursued with a unique change of "thickness-thickness." Fifth, in part 4 that is indicated theme 4, the other diversity was intensified with the inverted range in the front part and the middle part. Accordingly, based on the conclusions that were indicated in this work, it is desired to be conducive to understanding the horizontal consideration and the progression principle of orchestration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.208-215
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• 2020

This study investigated the relationship among gait variables and physical fitness variables for Korean elderly people. Two hundred elderly people aged 65 to 85, (100 men and 100 women) participated in this study. They performed senior fitness test consisting of 6 tests, 3 additional physical tests (vertical jump, one leg stand, and grip force), body composition measures, and gait test. The gait test used shoes having an inertia measurement device in the outer-soles. The results indicated that the stride length, 6-min walking, lean body mass, and dumbbell curls were significantly affected by age (the above 75 group vs. the below 75 group). Among 33 measured parameters, the principal component analysis (PCA) revealed five PCs such as gait characteristics, physical features, gait variability, and fitness levels. In addition, the correlation analysis showed that the preferred walking speed was significantly, positively associated with stride length and single support time, whereas it was negatively associated with double support time and gait variability.(Ed note: please confirm my modification) In conclusion, sarcopenia should be avoided in elderly people, and resistance exercise is highly recommended to help elderly people maintain their gait ability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.594-600
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• 2016

The present study numerically investigated the gas leakage characteristics in a simplified underground combined cycle power plant. The effect of obstacles near a crack location on the gas concentration in the confined space was analyzed by using the lower flammable limit (LFL) of methane gas. When the jet flow was close to the vertical walls, the longitudinal leakage distance increased by about 60% (when an obstacles was present) compared to the case without any obstacle, because these obstacles prevented transverse flows. In addition, when an air filter was installed near to the trajectory of the gas flow, the longitudinal leakage distance was similar to the distance between the crack and obstacle, whereas the transverse leakage distance increased up to 8 times compared to the case without any obstacle. As the jet flow impacts on the obstacle and changes its direction, the gas flows recirculate. Therefore, it is necessary to consider the effect of the structure and facility locations on the trajectory of the jet flow to propose an accident prevention system in confined spaces.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1339-1347
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• 2015

This study discusses a remote control torch system equipped with a GMAW double wire reel. The welding machine is 30m away from the wire feeder at the industrial site and the feeder is three to five meters away from the torch. Accordingly, the welders cannot control the current and voltage that meets the welding condition during work when they are working at a place that prevents them from seeing the control panel, such as inside a vehicle or tank or at a far work site. They also have no choice but to stop working to change the wire reel when it is burned out completely. Such work suspension resulting from frequent moves to adjust the current and voltage as well as to replace the wire and subsequent cooling causes welding defects. This study produced a remote control torch equipped with a double wire reel by simplifying and streamlining the existing GMAW functions to reduce the troubling issue. The remote control torch equipped with a double wire reel and the existing $CO_2$ /MAG welding torch were applied as a V-groove butt in the vertical position using 6mm rolled steel for a SM50A welding structure. After welding, the condition of welded surface beads underwent a visual inspection and radiographic inspection to analyze the welding quality inside the welded part. This study also evaluated the reduction of welding defects, cost saving, the replacing performance against the existing commercial welders, and the effects on possible compatibility.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1824-1832
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• 2011

In this paper, a smart home service robot McBot II is newly developed in much more practical and intelligent system than McBot I which we had developed a few years ago. Thus far, vacuum-cleaners have lightened the burden of household chores but the operational labor that vacuum-cleaners entail has been very severe. Recently, a cleaning robot was commercialized to solve but it also was not successful because it still had the problem of mess-cleanup, which pertained to the clean-up of large trash and the arrangement of newspapers, clothes, etc. Hence, we develop a new home mess-cleanup robot McBot II to completely overcome this problem on real environments. The mechanical design and the basic control of McBot II, which performs mess-cleanup function etc. in house, is actually focused in this paper. McBot II is mechanically modeled in the same method that the human works in door by using the waist and the hands. The big-ranged vertical lift and the shoulder joints to be able to forward move are mechanically designed for the operating function as the human's waist when the robot works. The mobility of McBot II is designed in the holonomic mobile robot for the collision avoidance of obstacle and the high speed navigation on the small area in door. Finally, good performance of McBot II, which has been optimally desinged, is confirmed through the experimental results for the control of the robotic body, mobility, arms and hands in this paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.470-477
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• 2013

The aim of this study is to suggest a detection method of water surface location and its evaluation results of application for same vertical position in two successive images with time interval including both staff gauge and water surface. A specific rectangular inspection area is defined from the top of watermark and then the correlation coefficients for the inspection area of the same position of two images with short time interval is calculated. Accordingly, it is possible to identify differences between changing area and fixed area of pixel density by the water flow. The photographs taken in the laboratory were analyzed in order to validate the proposed technique. As the result of the experiment, it is identified that characteristic of correlation coefficients depends on the size of the inspection area. In the case that the inspection area is within the entire width of the watermark, water surface characteristic according to correlation coefficients is clearly noticeable. Thus, it is identified that the proposed technique can be utilized to search water surfaces. Besides, using corelation analysis of two images with time interval, it is identified that error range between 10 and 42cm was reduced in the level of 2.6cm or less in the contaminated photo of existing image stage gauge. Therefore, it is expected that the suggested method can be utilized to enhance image stage gauge performance improving the previous water surface detection method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3513-3520
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• 2012

This study aimed to investigate the difference of the body orientation ability in sitting position to adapt to dynamically changing angle of the base of support in stroke patients and Healthy adults. The angle between vertical and head and trunk in 12 stroke patients (6 male and 6 female) and 12 healthy adults (6 male and 6 female) were measured by video motion analysis system. The head and trunk angle between stroke patients and healthy adults in sitting position were significantly different when increase the angle of dominant side(p<.05). The head and trunk angle between stroke patients and healthy adults in sitting position were significantly different when increase the angle of non-dominant side(p<.05). The head and trunk angle between stroke patients and healthy adults in sitting position were significantly different when decrease the angle of non-dominant side(p<.05). The head angle between stroke patients and healthy adults in sitting position was significantly different(p<.05), but the trunk angle was not significantly different when decrease the angle of dominant side(p>.05), Stroke patients compared to healthy adults had more deficits in their body orientation ability in sitting position to adapt to dynamically changing angle of the base of support. This finding may help to understand postural control deficits more clearly in stroke patients in sitting position.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.422-430
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• 2016

We investigated the abundance and composition of the zooplankton community around Dokdo in the East Sea from 2006 to 2015. Zooplankton samples were collected in the surface mixed layer by vertical hauls using a standard type net at the monitoring stations. There were no clear long-term trends in the average temperature and salinity, but relatively low salinity was recorded in the summer of 2013 and 2015. The average abundances of zooplankton in the summer increased by two orders of magnitude from $317inds./m^3$ in 2008 to $10,242inds./m^3$ in 2015. This long-term increase was accompanied by a slight increase in the chlorophyll-a concentration and a decrease in the catch of potential crucial predators (anchovy, mackerel pike, squid, herring and horse mackerel) in the study area. The dominant zooplankton, accounting for most of the long-term increase, consisted of appendicularian (Oikopleura spp.), which showed a steady increase since 2012, summer species such as Noctiluca scintillans and the cladoceran Penilia avirostris, which showed an abrupt increase, and the copepod Paracalanus parvus s.l., which showed a rapid increase after its first occurrence in summer 2010. These results suggest that the long-term increase of zooplankton could be related to the increase in the concentration of prey and the decrease in the predation pressure of potential predators around Dokdo in the study area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.554-561
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• 2016

In this study, loading tests and a strength evaluation of the bogie frame were conducted to verify the structural safety of the bogie system in an intermodal tram, which runs with cars on a road track. The loads were calculated taking into account the features of the road track with many sharp curves and steep gradients, which are different from the track of conventional railway. They were compared with the loads specified in the previous standard specifications. After the comparison, it was confirmed that the loads acting on the bogie system operating on a road track are slightly different from the specified loads. The specified vertical load of the standard specification for all kinds of trains is conservative, but the specified lateral and longitudinal loads are less than the calculated loads. The application of the actual loads was proven to be reasonable in the development of a new railway system. Based on the defined loads, the bogie frame was fabricated on which strain gauges were attached. It was set on the large loading frame so that the stresses could be measured when loads were applied by hydraulic actuators. After measuring the stresses, it was shown that they were below the allowable stress, which verified the structural safety of the bogie frame.