• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1384-1388
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• 2003

In structural fires, flashover is characterized by the rapid transition in fire behavior from localized burning of fuel to the involvement of all combustibles in the enclosure. An investigation of parameter effects on the time to reach flashover conditions in a typical single room fire is undertaken using a zone method (FAST) and Thomas method. Major parameters affecting the time to reach flashover are found to be fire growth rate, ventilation opening area and internal room surface. The results of the FAST and the Thomas Method give very similar results of the time to reach flashover..

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.459-464
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• 2011

It is prescribed for the controls layout of agricultural tractors to offer a comfortable workspace in ISO 4253 as international standard. To export other country to the Korea agricultural tractor, it needs to come up to the nation standard. The objective of the study is to investigate for location of control operation of the Korea agricultural tractor after applying the ISO 4253, to know whether it suits or not the nation standards with the tractor of product and supply within the country. As the research result of Korea agricultural tractor, Controls position of them are few in zone of comfort which defined in ISO 4253 and escapes lots in the zone of reach.

• Journal of Korean Society on Water Environment
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• v.34 no.5
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• pp.447-461
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• 2018

To realize river restoration that ecological characteristics of the river are reflected, we classified the river into four reaches of valley stream, upstream, midstream, and downstream based on substrate as well as riverbed gradient obtained from the relationship between distance from the river mouth, and above sea level. Considering that the rivers of Korea have been dominated by various and intense artificial interferences over a lengthy period, we determined cross sectional range of the river based on the geological map and clarified transformation degree by reach. Vegetation profile diagram was prepared by depicting horizontal range and vertical stratification of major vegetation appearing in a belt transect of 10 m breadth installed between weirs constructed in both sides of the river. Restoration models by river reach were prepared based on breadth of waterway, bare ground, herb, shrub, and tree dominated vegetation zones on vegetation profiles wherein a flooding regime was reflected. Species composition information collected from vegetation established in each zone was systematized to use for restoring each reach ecologically. Further, background that longitudinal reaches and horizontal zones were divided, was discussed by comparing with case studies in foreign countries. In addition, necessity of ecological restoration of the river was discussed based on degree of integrity of Korean rivers, ecological significance of riparian vegetation, and importance of reference information for ecological restoration of the river.

• Journal of the Korean Society of Marine Environment & Safety
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• v.7 no.1
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• pp.25-40
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• 2001

The coastal waters and the adjacent coastal lands strongly influenced by each other and includes islands, transitional and intertidal ares, salt marshes wetlands and beaches. We focus on the coastal zone because of its unique geographical characteristics, Its ecological and economic importance, and the increasing pressures on its integrity. Our coastal zone have been controlled individually about 50 of a different kind of laws, as a result, to reach an individual purpose of the laws, people have developed the coastal zone without considering environmental condition, which brought about ecological destruction, pollution and devastation of the coastal areas. Finally, In 1999, the Coastal Management Act and the Wetlands Conservation Act were established and hereafter the environmental concern has been increased. They will be an important role to preserve our environment of coastal zone. Here I will examine the Laws concerned with environmental management of coastal zone and indicate immanent problems of it. So, I expect that problems will be improved one by one through this paper.

• Korean Journal of Microbiology
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• v.19 no.3
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• pp.121-127
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• 1981

The constituents of molasses and effect of pH precipitate formation in molasses solution, vary according to its producing districts. The formation of precipitation is not so changeable in the range of buffering zone of molasses solution(pH4.3-6.3) in philippine molasses according to the change of pH value. On lower or higher than the range of buffering zone, the precipitation is increased from pH 4.3 to 2.8 and from 6.3 to 8.1, it is decreased when pH value is lower or higher than the pH value range. For molasses clarifying, it had better adjust the pH of molasses solution to neutral or weak alkali range out of the alkai side of the buffering zone, with lime solution. And then, add the calcium super phosphate solution to pH value of alkali side in buffering zone, as much as the pH of clarified molasses solution can reach to middle value in buffering zone. For the equilibrium of pH value on clarifying molasses, it takes plenty of time more than 6 hours.

• Environmental Engineering Research
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• v.25 no.1
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• pp.123-128
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• 2020

Non-point source pollutant load reductions were calculated using the Hydrologic Simulation Program-Fortran (HSPF) model under the assumption that landuse pattern was changed according to land purchases. Upon the simulation of non-point pollutant and areas with high land purchase ratios to select a buffer zone, the Namgang dam Reach 11, Imha dam Reach 10, and the Reach 136 watershed of the main river were found to rank high for the construction of buffer zones. Assuming that the forms of the purchased lands were changed to wetlands, biological oxygen demand (BOD) loads were changed through the HSPF model. No changes of BOD were present in the Namgang dam and the Imha dam watersheds. BOD loads in Reach 136 according to landuse change were analyzed through a flow duration analysis based on the total maximum daily loads of the United States. The flow duration analyses undertaken to examine changes in BOD of main river Reach 136 watershed indicated a shift of 0.64 kg/d from 3.16 to 2.52 during high flow. The change of BOD under the conditions of moist, mid-range and dry were 11.9%, 9% and 4.5%. At the low flow condition, the variation range in the BOD load was from 0.58 kg/d to 0.41 kg/d.

• Steel and Composite Structures
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• v.18 no.5
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• pp.1177-1195
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• 2015

Six specimens are tested to investigate the cyclic behavior of beam-to-column abnormal joints in steel moment-resisting frames, which are designed according to the principle of strong-member and weak-panel zone. Key parameters include the axial compression ratio of column and the section depth ratio of beams. Experimental results indicate that four types of failure patterns occurred during the loading process. The $P-{\Delta}$ hysteretic loops are stable and plentiful, but have different changing tendency at the positive and negative direction in the later of loading process due to mechanical behaviors of specimens. The ultimate strength tends to increase with the decrease of the section depth ratio of beams, but it is not apparent relationship to the axial compression ratio of column, which is less than 0.5. The top panel zone has good deformation capacity and the shear rotation can reach to 0.04 rad. The top panel zone and the bottom panel zone don't work as a whole. Based on the experimental results, the equation for shear strength of the abnormal joint panel zone is established by considering the restriction of the bottom panel zone to the top panel zone, which is suitable for the abnormal joint of H-shaped or box column and beams with different depths.

• ETRI Journal
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• v.35 no.5
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• pp.786-796
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• 2013

In this paper, we propose a hybrid time-division multiplexing and dense wavelength-division multiplexing scheme to implement a cost-effective and scalable long-reach optical access network (LR-OAN). Our main objectives are to increase fiber plant utilization, handle upstream and downstream flow through the same input/output port, extend the reach, and increase the splitting ratio. To this end, we propose the use of an arrayed waveguide grating (AWG) and an erbium-doped fiber amplifier (EDFA) in one configuration. AWG is employed to achieve the first and second objectives, while EDFA is used to achieve the third and fourth objectives. The performance of the proposed LR-OAN is verified using the Optisystem and Matlab software packages under bit error rate constraints and two different approaches (multifiber and single-fiber). Although the single-fiber approach offers a more cost-effective solution because service is provided to each zone via a common fiber, it imposes additional losses, which leads to a reduction in the length of the feeder fiber from 20 km to 10 km.

• Journal of Biosystems Engineering
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• v.23 no.2
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• pp.157-166
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• 1998

In this study. a traveling control system was developed to transfer a machine without an operator in the working zone. The dimension of the system was modelized to design and construct smaller than that of real configuration of a greenhouse. For this system, the fixed path type was used to detect exact position during operating a manless machine. and the X-Y table actuator type to escape a unique path, which had the disadvantage in a fixed path type environment. Based on the results of this research the following conclusions were made : 1. This system used two screws to move toward horizontal direction, and a Plate to reach at any points in the working zone. 2. The software combined the functions of path selection and motor operation to control into one program. The path selection program was a menu driven program written in Visual Basic, and the motor operation program was written in Borland C++ for actuating motors. 3. The path-select mode of the program was used by selecting the desired paths, and the user path-create mode by selecting a random path in the path-selection program. 4. The system proved to be a reliable system for operating a manless machine, since accuracy and precision to reach the positions were less than 1%.

• Journal of the Korean Geographical Society
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• v.42 no.3 s.120
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• pp.388-404
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• 2007

This study interprets evolution of fluvial terraces along the four Yeongdong- and Yeongseo streams such as Naerin River, Yeongok River, Golji River and Osip River, in Gangwon Province based on the tectonics. The results from the analyses of the distribution pattern of fluvial terraces and incision rates of rivers show distinctively the evidence as the axis of uplift by Taebaek Mountains, especially on the 4th, 5th and 6th terraces in upper reach of Osip River among the four streams. The axis of uplift extends to the zone of $30\sim40km$ in width as well as the divide. The difference of uplift between upper and middle reaches of Naerin River and total reach of Golji River wasn't found from the height from riverbed by the active uplifting along all reaches, estimated to be set in inner area of uplift zone. Incision rate of period between formation age of 2nd terrace and 1st terrace is calculated $0.13\sim0.22m/ka$, and incision rate of period between formation age of 1st terrace and Present is diversely calculated $0.17\sim0.27m/ka$ by the climatic discrepancy between the two periods. The incision rate of Yeongdong streams whose mouths reach to the sea level eroded actively more than Yeongseo streams in the uplift zone. And Yeongdong streams between formation age of 1th terrace and present appears to much higher than that of Yeongseo streams, due to active down-cutting in oder to balance against the sea level.