• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1791-1796
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• 2005

Semi-shield tunneling is one of the propulsion construction methods used to lay pipes underground between two pits named 'entrance' and 'destination', respectively. Usually a simple composition, such as 'a fiducial target at the entrance+a total station (TS)+a target on the machine', is used to confirm the planned course. However, unavoidable curved sections are present in small-sized pipe lines, which are laid after implementation of a road system, for public works such as waterworks, sewer, electrical power, and gas and communication networks. Therefore, if the planned course has a curved section, it is difficult to survey the course with the abovementioned simple composition. This difficulty could be solved by using the multiple total stations (MTS), which attaches the cross type linear LED target to oneself. The MTS are disposed to where each TS can detect the LED target at the other TS or the base point or the machine. And the accurate relative positions between each MTS and target are calculated from measured data. This research proposes the relative and absolute coordinate calculation algorithm by using three MTS to measure a curved course with 20m curvature at 30m maximum distance, and verifies the algorithm experimentally.

• Journal of Korean Society of Rural Planning
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• v.14 no.1
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• pp.33-41
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• 2008

The main entrance is even disappeared nowadays when the component type is changed, because it loses the actual function. On the other hand, the type of main entrance is changed variously depended on the materials for house and method of construction. Eleven points in the Chungyang-Gun where the environment of rural villages is well maintained was choosed researched to make data. These data of visual component elements were analysed by using the SPSS 12.0 Windows. Cluster Analysis and Factor Analysis was performed to analyze the different types of main entrance in the rural villages. From the above research, we could conclude below results. Research result, The whole quality of the farming village gate with fine feeling and constant temperature characteristic order appeared with the fact that preference quality is highest, in afterwords was analyzed. Also the research which sees led and the result which appears from the landscape quality analysis which the residential gates are general and type by landscape quality analysis the result which appears with the comparative analysis overcomes the limit which the residential gates are general and type by landscape quality analysis the result which appears with the comparative analysis overcomes the limit which the abstractive landscape image has. Like this research result judges currently the research which is meaning which provides a planning standards and the guideline which the governmental department and the rural village improvement enterprising public opinion rural village residential enterprise which is propelling from oneself are detailed. Specially about landscape quality of the residential gate that presents a type classification and preference quality from the actual condition where the research is insufficient the hereafter rural village improvement enterprise specially, sees with the fact that will be the possibility of affecting is meaning to residential section the succeeding researches actively, there being could be advanced, wishes.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.68-78
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• 2006

In the past few years, considerable efforts have been directed towards the further development of Urea-SCR(selective catalytic reduction) technique for diesel-driven vehicle. Although urea possesses considerable advantages over Ammonia$(NH_3)$ in terms of toxicity and handling, its necessary decomposition into Ammonia and carbon dioxide complicates the DeNOx process. Moreover, a mobile SCR system has only a short distance between engine exhaust and the catalyst entrance. Hence, this leads to not enough residence times of urea, and therefore evaporation and thermolysis cannot be completed at the catalyst entrance. This may cause high secondary emissions of Ammonia and isocyanic acid from the reducing agent and also leads to the fact that a considerable section of the catalyst may be misused for the purely thermal steps of water evaporation and thermolysis of urea. Hence the key factor to implementation of SCR technology on automobile is fast thermolysis, good mixing of Ammonia and gas, and reducing Ammonia slip. In this context, this study performs three-dimensional numerical simulation of urea injection of heavy-duty diesel engine under various injection pressure, injector locations and number of injector hole. This study employs Eulerian-Lagrangian approach to consider break-up, evaporation and heat and mass-transfer between droplet and exhaust gas with considering thermolysis and the turbulence dispersion effect of droplet. The SCR-monolith brick has been treated as porous medium. The effect of location and number of hole of urea injector on the uniformity of Ammonia concentration distribution and the amount of water at the entrance of SCR-monolith has been examined in detail under various injection pressures. The present results show useful guidelines for the optimum design of urea injector for reducing Ammonia slip and improving DeNOx performance.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.5
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• pp.71-78
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• 2018

This study seeks to identify elements of spatial planning for areas surrounding children's parks in order to improve child safety. It will identify different aspects of child safety and extract elements of safety planning for the areas surrounding children's parks from a literature review of both domestic and international research. The study classifies the space between one's residence and the children's park as either a "means of access", such as pedestrian walkways and streets, or a "boundary", which consists of the entrance, exit, and fences; then, the derived safety planning elements were categorized in accordance with this classification. In order to ensure the validity of the planning elements, an expert survey was conducted of environment planners who specialize in the palnning and designing of residential area as well as government employees who are in direct charge of managing children's parks. The survey findings were as follow. First, the pedestrian walkway(means of access) near the park is the most crucial factor in regards to the safety of children, followed by the entrance and exit(boundary), fency(boundary), and streets (means of access), in descending order of importance. Thus, improving the safety of the pedestrian walkway should be considered first and foremost, and it should precede improving the surrounding streets. Second, an investigation of the need for safety devices near the children's park showed that securing visibility, through the installation of an illegal parking prevention device, is imperative. Illegal parking near children's parks poses a grave risk to pedestrian safety and demands immediate action. Furthermore, a section of streets within 300m of the park entrance should be designated as a children protection zone, in addition to the designation of school zones near elementary schools.

• Communications of Mathematical Education
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• v.27 no.4
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• pp.567-580
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• 2013

As integrated essay writing is performed in university entrance examinations, teachers and students recognize the importance of integrated essay, but teachers have still difficulties of teaching methods. The purpose of this study is to derive educational implications through case of mathematics instruction for integrated essay education to pre-service mathematics teachers. The content knowledge of this class is a definition of conic section in mathematics and properties of conic section in an antenna reflector. The students have to discover them using the history of math, manipulative material, paper-folding and computer simulation. In this teaching and learning process the students can realize mathematical knowledge invented by humans through history of mathematics. The students can evaluate the validity of that as create and justify a mathematical proposition. Also, the students can explain the relation between them logically and descript cause or basis convincingly in the process of justifying. We should keep our study to instructional materials and teaching methods in integrated essay education.

• Journal of architectural history
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• v.26 no.4
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• pp.35-44
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• 2017

The purpose of this study is to classify three-Kan hipped and gable-roofed Buddhist temples with the construction of their eave curve of part chunyeo and examine the characteristics and causes. The conclusions have been drawn as follows: First, there are largely three ways to secure symmetry in eave curve of part chunyeo. One is to obtain symmetry in eave curve of part chunyeo by making the size of eaves curves on well sides the same and forming symmetric curves in the front section along with the side roof and then forming the straight line in the central part (hereinafter referred to as the long straight line section method). The second is a method to enlarge eaves curves in the front and form eaves curves on the roof section to be symmetric (hereinafter referred to as the front is larger than side eaves curves method). The third is the method to make eaves curves in the roof section to be symmetric by adjusting the roof length and making difference between the front and side roof's length minimum (hereinafter referred to as the roof length-controlling method). Second, there are 16 cases applying two or more methods, and they are the mainstream. Third, there are 12 cases applying the front is larger than side eaves curve method and roof length-controlling method both, which seems to be the most universal. To sum up, they secured symmetry in roof edges considering the construction of seonjayeon and pyeongyeon according to the size of the structure, recognition on the directions of entrance into the area of the building, forms of planes, harmony with structures around, recognition on roof curves in accordance with the size, and also structural faults in the chunyeo part.

• Journal of Korean Port Research
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• v.13 no.2
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• pp.333-350
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• 1999

Today freeway is thought to be a very important transportation facility carrying tremendous traffic flow as the main corridor within the area of between the areas. However freeway is experiencing severe congestion and accidents by increased entrance ramp flow especially at peak time period. Ramp meters on the freeway entrance ramps that supply traffic to the freeway in a measured or appropriately regulated amount are needed for alleviating freeway congestion. Because ramp meters can be operated to discharge traffic at a measured or regulated rate thus maintaining more uniform speed on the mainline section maximizing the throughput to the freeway within the capacity of a downstream bottleneck and reducing the congestion related accidents. Thus the objectives in this study were to analyze the traffic characteristics on the freeway I-94 with ramp metering system before/after ITS technology in Detroit (Michigan) area compare shifts of the traffic characteristics on the freeway I-94 before/after ITS technology and finally suggest a better ramp metering strategy for the freeway system The following results were obtained: i)Flow occupancies and speeds on the mainline merge section of freeway were shown to be a big difference depending on the peak periods areas and directions based on the distribution of traffic flow characteristics on the freeway. ii)Reduced speed was shown to be more than 5 mph and ramp flow was also shown to be more than 240 vph at peak periods if there was the ramp metering system constructed on the freeway. iii)Ramp metering system was shown to be optimally operated on the freeway if ramp flow could be maximized within the range of over 900 vph and reduced occupancy could be also maximized by no more than 2 percent at peak periods. iv)The average flows on the freeway after the ITS technology were shown to be a decrease of over 20% depending on the peak periods areas and directions when compared with those flow on the freeway before the ITS technology. over 20% depending on the peak periods areas and directions when compared with those speeds on the freeway before the ITS technology. vi)The average metering rates on the freeway after the ITS technology were shown to be an increase of over 10% depending on the peak periods areas and directions when compared with those metering rates on the freeway before the ITS technology.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.303-308
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• 2004

The failure at the head section of rubble mound breakwaters is more important than other failure modes. because this initial failures will occur the failure of the trunk section and lead to the instability of the structure. The three-dimensional failure modes are discussed using the experimental data with multi-directional waves considering the failure modes. It was occurred by the topographical characteristics around the head of rubble mound breakwater. The spacial characteristics of failure mode around the rubble-mound structures can be summarized as follows: 1) It was clarified that the failure modes at the round head of a detached breakwater are classified as failure by plunging breaker on the slope, failure by direct incident wave force and failure at the rubble mound breakwaters. 2) The failure mode was found in the lower wave height than the design wave by the breaker depth effects and topography around structures. It is clarified that the structure was monitored safely designed for the design wave but the failure was occurred by the reason of breaker waves.

• Journal of Korean Association for Spatial Structures
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• v.20 no.2
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• pp.95-104
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• 2020

Phaya-Thon-Zu temple has a unique architectural style connected by the three temples, and cultural values are highly as murals remain on some of the walls. However, various damages in internal walls and vaults have occurred due to earthquake and environmental influences. In order to analyze these damages, accurate structural analysis is required, but structural modeling is difficult, because Phaya-Thon-Zu temple is the complex masonry structure which is stacked with small bricks. Therefore, this study intends to analyze the causes of damages by examining collapse mechanism for cross section and longitudinal section of vaults in the entrance hall and shrine by using thrust line analysis, which is a geometric method, and to compare it with the actual damage situation.

• Journal of the Korean Society of Combustion
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• v.3 no.1
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• pp.59-69
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• 1998

The results of study on the active control of naturally occurring combustion oscillations with a single dominant frequency in an atmospheric dump combustor are presented. Control was achieved by an oscillatory infection of secondary fuel at the dump plane. A high speed solenoid valve with a maximum frequency of 250Hz was used as the actuator and a sound level meter, located at the combustor exit, measured the pressure fluctuations which served as the feedback signal for the control loop. Instability characteristics were mapped over a range of mean mixing section velocities from 6.7 m/s-9.3 m/s and with three mixing conditions. Different fuel/air mixing conditions were investigated by introducing varying percentages of primary fuel at two locations, one at the entrance to the mixing section and one 6 mixing tube diameters upstream of the dump plane. Control studies were conducted at a mean velocity of 9.3 m/s, with an air temperature of $415^{\circ}C$, and from flame blowout to the stoichiometric condition.