• ETRI Journal
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• v.26 no.2
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• pp.185-188
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• 2004

In this paper, we design a two-step scheduling algorithm to support multiple bandwidth allocation policies for upstream channel access in an Ethernet passive optical network. The proposed scheduling algorithm allows us a simultaneous approach for multiple access control policies: static bandwidth allocation for guaranteed bandwidth service and dynamic bandwidth allocation for on-demand, dynamic traffic services. In order to reduce the scheduling complexity, we separate the process of the transmission start- time decision from the process of grant generation. This technique does not require the timing information of other bandwidth allocation modules, so respective modules are free from a heavy amount of timing information or complex processing.

• Proceedings of the KIEE Conference
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• summer
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• pp.251-253
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• 2004

Nowadays, power customer has increased and new power plants have been constructed for market demands. However, increasement of power plants make power system more complex and unstable. For this reason, the stability problem is one of the most important issues in power systems. In this paper, a study on implementation of out-of-step detection algorithm is performed. The structure of digital relay is analyzed for development of out-of-step detection algorithm. DFT block which is used to extract basic frequency of voltage is analyzed to design VHDL.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.105-112
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• 2013

The new renewable energy became popular as a clean and sustainable alternative energy under the circumstances that the entire world is facing severe abnormal climate due to the use of fossil fuel, and among which, solar energy can be obtained anywhere and is not difficult to apply it into the existing buildings, which makes it possible to be widely distributed. However, as PV module is installed into a single plate system, it shows structural weaknesses which are vulnerable to wind load and give loss to design elements in external appearance. Accordingly, this study planned one-step parallel system to complement the problems occurring from a single plate system and used STAR-CCM+ V.8 made by CD-Adapco, a computational fluid dynamics(CFD) simulation tool to measure wind load stability and support based on the design standards for a single plate system and one-step parallel system. Building height was limited to less than 10m and wind speed was given when increasing from 35m/s to 50m/s by 5m/s on PV system installed into the flat roof. In this case, our analysis suggested that step-one parallel system was in class 7-9 according to Beaufort's wind power classification, which did not have an impact on the fixed PV system, and the single plate system is considered to cause risks in designing wind speed in central districts because it is more than wind power class 12.

• Journal of the Korean Society of Costume
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• v.24
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• pp.177-192
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• 1995

The purpos대 f this research was to figure out clothing imagery underlying Shakepeare's King Lear and transfer it into actual stage costume. Three steps were taken in order to achieve the purpose . The first step exemined theoretical background of the Shakepeare's imagery. The second step reviewed a wide spectum of stage costume used in the last four centuries. The final step was to design and produced actual stage costume focusing on Lear, while considering clothing imagery drawn from the previous steps. King Lear contained rich clothing imagery which could contrast the relationship between material and spirit. In particular, it shed light on the contrast between Lear's divesting and Edgar's wearing and denoted that wearing and divesting processes were closely related to spiritual and status changes. A review of stage costume used for four centuries was prepared in order to understand how clothing imagery was applied in producing stage costume. It was found that their stage costume was reflecting clothing imagery captured from the analysis of king Lear. On the basis of this review, this research presented Lear's stage costume which applied clothing imagery drawn from King Lear. In producing stage costume , actual stage costume used Elizabethan fashion as its basic color and pattern. It also utilized modern clothing production techniques and ornaments acceptable in these days. As Lear was depicted as a character who underwent spiritual and status changes in the process of divesting , his costume was produced in line with this clothing imagery (i.e., divesting). The long journey of reviewing and analyzing King Lear from a stand point of clothing reassured us, on the one hand, the importance of stage costume. On the other hand, it established the groundwork for developing the methodology of fashion design by applying clothing imagery drawn from literature to design and production of stage costume.

• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.27-35
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• 2022

This study aims to provide an industry-university cooperation cap in a non-face-to-face environment so that sharing and cooperation between universities can be shared based on the advanced digital technology between various universities at a time when it is rapidly changing to an online mode. It is in developing the stone design course. To this end, we analyzed the literature and previous studies on non-face-to-face environments and capstone design, developed a model for industrial-educational collaboration-type capstone design subjects in non-face-to-face environments, and suggested an application plan. The wearable capstone design program was pilot-applied, and the effectiveness was confirmed and corrected through the students' interview and questionnaire. This can be used as an industrial-educational cooperation engineering class capstone design class plan, providing basic data for development and operation, and as a step-by-step operation guide in a non-face-to-face environment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.3
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• pp.183-190
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• 2008

The maintenance and management of each tunnel has been individually performed in depending on service, management agency, and tunnel size. The maintenance and management system for the existing tunnel consists of simple tunnel card and the computerization of basic tunnel data, now. There is not the systemic maintenance and management system for tunnel. Therefore, it has been impossible the systemic maintenance and management for tunnel due to loss of data obtained from each step, such as, plan, design, construction, or maintenance, with time. The objective of this study is to build the database system in combing the results of tunnel scanning with all data obtained from plan, design, construction, or maintenance step.

• Korean Journal of Construction Engineering and Management
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• v.10 no.3
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• pp.32-41
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• 2009

In the execution of construction management, such pre-design steps as a planning stage, a basic design stage, and a work design stage are regarded as more important than an actual construction stage. However, the manpower input criterion from the aspect of construction management price standard in the Construction Engineering Management Law does not attach weight to the pre-design stage. In this regard, the aim of this study was to examine the propriety of manpower input in the pre-design stage of construction management and then present an improvement strategy of it. For this, the investigator examined the criterion of service price prescribed in the Construction Engineering Management Law and then comparatively analyzed four sites of construction management services. Study findings are as follows: 1) the actual state of manpower input based on the stepwise average price criterion of construction management service is presented with such steps as the newly established planning step (6.6%), the basic design stage (3.9%$\rightarrow$5.6%), the practical design stage(7.6%$\rightarrow$13.5%), the construction stage (88.5%$\rightarrow$64.0%), and the newly established maintenance stage (10.3%). The average price criterion is classified by total construction expenses and calculated by improved rates and stage; and 2) the three-step criterion of the Construction Engineering Management Law is classified into five stages including the planning stage and the maintenance stage by dividing it with the stepwise construction businesses. Study findings show that the calculation of price criterion in the actual site of construction management services must be operated in a practical and flexible manner and the systematic improvement of stepwise manpower input must be carried out actually.

• Journal of the Korean Home Economics Association
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• v.47 no.2
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• pp.111-123
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• 2009

This study is to explore the usability of a pattern making software 'Looks tailor X' developed recently by the Digital Fashion in line with the cloth simulation software 'DressingSim'. When the software engineers develop software for clothes and clothing simulations, most often they lose touch of real-world craftsmanship of pattern making. As such, the software evaluation of the functionality and the usability is a crucial step in the field of virtual clothing. We carried out a detailed evaluation of the software via the process of making some basic types of pattern including tight skirts, pants, jackets, and one-piece dress. In this paper, we documented a step-by-step scenarios of making clothes using the Looks tailor X, and listed both the advantages and limitations of the software from the perspective of an enduser, i.e., a professional fashion designer. We also briefed suggestions on the refinement of the future software in the field.

• 한국전산유체공학회:학술대회논문집
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• 1998.05a
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• pp.168-173
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• 1998

A numerical analysis of axisymetric backward facing step main nozzle flow in air jet loom has been accomplished. To obtain basic design data for an optimum main nozzle for an air-jet loom and to predict the transonic/supersonic flow, a characteristic based upwind flux difference splitting compressible Navier-Stokes method has been used. The wall static pressure of the main nozzle and the flow velocity changes in the nozzle tube were analyzed by changing air tank pressures and acceleration tube lengths. The flow inside the nozzle experiences double choking one at the needle tip and the other at the acceleration tube exit at tank pressures over $4kg_f/cm^2$. The tank pressure $P_t$ leading to the critical condition depends on the acceleration tube length; i.e, $P_t$ is higher for longer acceleration tubes. The $P_t$ value required to bring the acceleration tube exit to the critical condition is nearly constant regardless of acceleration tube length. The round needle tip shape might lead to less total pressure loss when compared with step shape.

• Journal of Mechanical Science and Technology
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• v.16 no.6
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• pp.839-850
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• 2002

A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator. Characteristics of components including compressors, turbines, power turbines and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components'characteristics with the scaling law. The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator. In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque. The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the turbine inlet temperature occurred. However, in case of ramp increase of the fuel longer than step increase of the fuel, the overshoot of the turbine inlet temperature was effectively reduced.