• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.3
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• pp.34-43
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• 2021

Wake turbulence generated by the lead aircraft has a significant impact on the following aircraft and it is has been considered a key factor to consider whenin determining the longitudinal separation between the aircraft. ICAO classifies aircraft into four wake turbulence categories based on the maximum takeoff weight and provides the longitudinal separation minima for each category. Due to richer measured data and better understanding of physical processes, it is raised that classifying aircraft with only four wake turbulence grades is imprecise and leads to over-separation in many instances. In this regards, much research on a new method of classifying Wake Turbulence Category(Re-CAT) has been done by EURO-CONTROL, FAA, and ICAO. The main purpose of this study is to conduct a comparative analysis of the existing wake turbulence separation standards with Re-CAT in terms of departure capacity and the resulting benefits of Re-CAT using the data from the Incheon International Airport. The results show that EUROCONTROL and new ICAO standards have the greater effect on reducing wake turbulence separation, compared to the FAA RE-CAT standards. It is also concluded that Re-CAT presents different results of wake turbulence separation depending on the flight characteristics of each airport.

• Journal of Korean Society for Quality Management
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• v.51 no.2
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• pp.185-202
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• 2023

Purpose: The purpose of this study is to identify key performance evaluation items and factors that are effective and practical for project management of defense standard standard improvement projects, and to develop a quantitative performance evaluation model. Methods: For the development of a performance evaluation model for defense standard improvement projects, we analyzed past major project performance and derived evaluation items and factors. To increase the objectivity and efficiency of project evaluation, we developed an evaluation index that enables relative evaluation of evaluation targets, and calculated the main importance of evaluation items using the Analytic Hierarchy Process (AHP) method based on the main opinions of expert groups. Results: The study resulted in the identification of main performance items for defense standard improvement projects, which were classified into defense standard conformity review performance and defense standard improvement performance items. We also simplified the evaluation model by integrating various evaluation items into similar evaluation factors. Additionally, we developed a quantitative evaluation index that enables relative evaluation of the targets and verified the objectivity and validity of the suggested performance evaluation model by reevaluating it using performance data from past commissioned professional institutions Conclusion: Developing a quantitative evaluation model for defense standard improvement projects is expected to provide a means of measuring the effectiveness of the project, and to be used as a tool to determine the appropriateness and effectiveness of medium and long-term project plans.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2317-2323
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• 2024

Medical linear accelerators with an energy of 8 MV or higher are radiated owing to photonuclear reactions and neutron capture reactions. It is necessary to quantitatively evaluate the concentration of radioactive isotopes when replacing or disposing them. HPGe detectors are commonly used to identify isotopes and measure radioactivity. However, because the detection efficiency is generally calibrated using a standard material with a density of 1.0 g/cm³, a self-absorption effect occurs if the density of the measured material is high. In this study, self-absorption correction factors were calculated for tungsten, lead, copper, and SUS-303, which are the main materials of medical linear accelerator head parts, for each gamma-ray energy using MCNP 6.2 code. The self-absorption effect was more pronounced as the energy of the emitted gamma rays decreased and the density of the measured materials increased. These correction factors were applied to the radioactivity measurements of the in-built and portable HPGe detectors. Furthermore, compared to the surface dose rate measured by the survey meter, the accuracy of the measurements of radioactivity improved by an average of 124.31 and 100.53 % for inbuilt and portable HPGe detectors, respectively. The results showed a good agreement, with an average difference of 3.70 and 5.24 %.

• Journal of Technology Innovation
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• v.23 no.3
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• pp.225-253
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• 2015

The standard is a nation's one of the most important industrial issues that improve the social and economic efficiency and also the basis of the industrial development and trade liberalization. This research analyzes the enactment and the utilization of Korean industrial standards(KS) of various industries. This paper examines Korean industries' KS utilization status based on the KS possession, enactments and inquiry records. First, we implement multidimensional scaling method to visualize and group the KS possession records and the nation's institutional issues. We develop several hypothesis to find the decision factors of how each group's KS possession status impacts on the standard enactment activities of similar industry sectors, and analyzes the data by implementing regression analysis. The results show that the capital intensity, R&D activities and sales revenues affect standardization activities. It suggests that the government should encourage companies with high capital intensity, sales revenues to lead the industry's standard activities, and link the policies with the industry's standard and patent related activities from R&D. Second, we analyze the impacts of each KS data's inquiry records, the year of enactments, the form and the industrial segment on the utilization status by implementing statistical analysis and decision tree method. The results show that the enactment year has significant impact on the KS utilization status and some KSs of specific form and industrial segment have high utilization records despite of short enactment history. Our study suggests that government should make policies to utilize the low-utilized KSs and also consider the utilization of standards during the enactment processes.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.6
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• pp.22-33
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• 2009

This study was undertaken to provide a basis for planning trail standards, providing rights of movement, improvement of health and the experience of nature for at-risk walkers for application to the Umyen Park site. This study researched related laws, manuals, scholastic writing and the established site, a raku-raku mountain trail in Osata, Japan. By referencing these results and similar standards, a conceptual trail plan for at-risk walkers was created. The plan suggests five points -- accessibility, convenience, social aspects, economic efficiency, and environmentally-friendliness -- and referenced an evaluation of outdoor living environments for the elderly. The planning standards are comprised of four steps that are ranked in order and are related to the selection of location, trail structure, route patterns, and equipment. Plans for trails catering to at-risk walkers in Umyen Park were then based on these standards. As a result, it was found that the mountain has both a high elevation and abundant natural resource, both of which must be taken into account during planning. This study is valuable because it is one of the first studies of trail plans for at-risk walkers made in mountainous urban parte. Subsequent research can use the standards of this study for further evaluation while future modifications must reflect changing needs and details.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.218-225
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• 2020

This study analyzed the priorities of the cross-compliance items of public-benefit direct payment using an Analytic Hierarchy Process and Fuzzy Decision Making Analysis. The valuation criteria are policy efficiency, farm acceptability, and feasibility, and the valuation targets are the basic and additional cross-compliance items. The survey was performed by targeting 50 experts from each class, and conducted for about a month starting from the beginning of July 2019. The results show that the weight of the valuation criteria is higher in the order of farm acceptability, feasibility, and policy efficiency. Compliance with PLS standards, compliance with disposal standards of waste vinyl and pesticides, soil testing, compliance with toxic substance standards, education, etc. are comparatively evaluated to be higher cross-compliance items in basic cross-compliance. Disposing of an abandoned well, jointly collecting and disposing of agricultural by-products, common area care and cleaning, maintenance of empty houses and poor facilities, growing green manure crops during the fallow period, etc. are comparatively evaluated to be higher cross-compliance items for the additional cross-compliance. The results of this study are expected to contribute to the government's policy related to the cross-compliance of public-benefit direct payment.

• Journal of Internet of Things and Convergence
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• v.7 no.3
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• pp.9-14
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• 2021

This paper discovers the energy loss factors through the insulation diagnosis of houses or buildings, and proposes directions for energy efficiency improvement. The energy efficiency factor of a building consists of insulation diagnosis, thermal bridge diagnosis, window diagnosis, airtight diagnosis, and equipment diagnosis. Among the residents and facilities in the energy welfare blind spot, an energy efficiency diagnosis was conducted for one senior citizen building located in Naju-si, Jeollanam-do, and energy efficiency diagnosis was conducted after insulation was installed. Energy measurement, diagnosis and analysis were performed using the IoT-based integrated wired/wireless energy diagnosis platform, Energy Finder. As a result of comparison, an overall energy saving rate of 16.38% was achieved. Annual heating energy consumption per unit area decreased from 333.51kWh before construction to 277.35kWh after construction, and annual cooling energy consumption per unit area decreased from 5.51kWh before construction to 5.22kWh after construction. The annual primary energy consumption per unit area decreased from 464.52kWh before construction to 403.69kWh after construction, and the annual energy cost was reduced from 3,063,307.14 won before construction to 2,641,072.49 won after construction. The additional improvement work is needed on the standards affecting energy efficiency other than insulation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.3
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• pp.88-96
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• 2007

H.264 is a new international video coding standard that can achieve considerably higher coding efficiency than conventional standards. Its coding gain has been achieved by employing advanced video coding methods. Specially, the increased number of macroblock modes and the complex mode decision procedure using the Lagrangian optimization are the main factors for increasing coding efficiency. Although H.264 obtains improved coding efficiency, it is difficult to do an real-time encoding because it considers all coding parameters in the mode decision procedure. In this paper, we propose a fast mode decision algorithm which classifies the macroblock modes in order to determine the optimal mode having low complexity quickly. Simulation results show that the proposed algorithm can reduce the encoding time by 34.95% on average without significant PSNR degradation or bit-rate increment. In addition, in order to show the validity of simulation results, we set up a low boundary condition for coding efficiency and complexity and show that the proposed algorithm satisfies the low boundary condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.970-976
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• 2013

An evaluation of the organic matter removal efficiency showed high removal efficiencies of 91.1~96.3% and 91.4~97.5% for TCODcr and TBOD5, respectively, for 9hr or longer of HRT. However, the removal efficiencies decreased to 86.9~90.5% and 88.0~90.9%, respectively for 6hr of HRT. $NH_3$-N showed a high removal efficiency of 95% or higher for 9hr or longer of HRT. The total nitrogen removal efficiency was 67.6~76.7% for 9~12hr of HRT, and it decreased to 50% for 6hr of HRT, which seems to be due to the insufficient carbon source required for denitrification. The T-P removal efficiency was 32% on average. To comply with the legal standards, a chemical phosphorus removal process is needed after the reactor.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.354-362
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• 2012

Recently, High Efficiency Video Coding (HEVC) is under development jointly by MPEG and ITU-T for the next international video coding standard. Compared to the previous standards, HEVC supports variety of splitting units, such as coding unit (CU), prediction unit (PU), and transform unit (TU). Among them, it has been known that the recursive quadtree structure of CU can improve the coding efficiency while the encoding complexity is increased significantly. In this paper, a simple conditional probability to predict the early termination condition of recursive unit structure is introduced. The proposed conditional probability is estimated based on Bayes' formula from local statistics of rate-distortion costs in encoder. Experimental results show that the proposed method can reduce the total encoding time by about 32% according to the test configuration while the coding efficiency loss is 0.4%-0.5%. In addition, the encoding time can be reduced by 50% with 0.9% coding efficiency loss when the proposed method was used jointly with HM4.0 early CU termination algorithm.