• Journal of Positioning, Navigation, and Timing
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• v.3 no.2
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• pp.83-90
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• 2014

In this study, to improve an existing ground-wave based time broadcasting system, a study that predicts the field distribution and field strength of the transmitted signal of a new ground-wave based time broadcasting system was performed. The prediction area was assumed to be the Korean peninsula; and to reflect the mountainous terrain of the Korean peninsula in the prediction of the variations of field distribution and field strength, a new prediction method based on the Monteath model was proposed and utilized. As field distribution changes depending on the position of a transmitter station, potential sites for the transmitter station were selected considering the geographical characteristics. In this regard, the ground conductivity information of North Korea cannot be obtained, and thus, the ground conductivity of the North Korean region was reflected considering the geological characteristics of South Korea and North Korea. Based on this, the variations of field distribution and field strength were predicted by setting the Korean peninsula as the prediction area, and the prediction results depending on the position of the transmitter station were discussed.

• Journal of Soil and Groundwater Environment
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• v.15 no.3
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• pp.1-6
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• 2010

This study investigated the change of metal contamination levels according to amendment of enforcement regulation of the Soil Environmental Conservation Act in Korea. As an analytical result of 87 samples in abandoned metallic mine area, the extracted amount of As, Pb and Cu with aqua regia was 4.3~29.6 times higher than that with hydrochloric acid extraction and the number of samples, which contamination levels were found to exceed soil contamination standards, was also increased. On the other hand, in case of Cd, Zn, and Ni, the number of samples, which contamination levels were found to exceed soil contamination standards, was decreased or similar. These results can be used as a preliminary material in comparison between the soil pollution data accumulated previously and the data obtained by the revised standard method for the examination of soil pollution.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.52-56
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• 2018

Extracorporeal shockwave therapy has been widely spread out showing an excellent efficacy compared to traditional medicinal treatments, interventional procedures or surgeries for diseases of tendons and musculoskeletal system. Major performance tests of extracorporeal shockwave therapy consist of pressure, energy flux, concentration, and effective amount of energy on the focus area of shockwave according to IEC 61846. Shockwave should be irradiated accurately to the lesion area to improve the performance of extracorporeal shockwave therapy, which makes it necessary to add the relevant section, IEC 60601-2-36 (12.1.101. Precision of Target Markers and Target Locations). International standards of extracorporeal shockwave therapy have been prepared based on European and western people. Thus, we need to conduct many studies on Korean patients to improve the quality of extracorporeal shockwave therapy and to develop the medical industry. In addition, the performance evaluation of extracorporeal shockwave therapy which has been prepared according to international standards should be additionally modified and supplemented corresponding to the Korean circumstances.

• Journal of the Korean housing association
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• v.9 no.2
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• pp.33-41
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• 1998

To accomodate increasing housing shortage in many cities, Korean Government has implemented various residental land development projects to provide more land for new housing construction. Most of the residential areas developed by these projects were used for multi-family housing units. Under this process, the size and location of the neighborhood service facilities in the development area were regulated by uniform standards. For this reason, the neighborhood service facilities were not able to be provided according to the household density but provided in minimum status required by these standards. Based on these considerations, this study aimed to evaluated residential land development project conducted by pubilc authority, one of the residential land development projects in Korea. Results of the case studies confirmed findings from literature review and proposed that existing regulations applied to these projects need to be amended not only to accomodata unique situation of each development area but also to enhance level of the dwelling environment. As ways to resolve these problems, this study suggests followings: (1) more flexible operation of the regulations, (2) inclusion of the socio-economic characteristics of the perspective resident in planning process, and (3) introduction of design techniques in the project. Finally, this study proposed future study directions in relation to this issue.

• Journal of the Korean Institute of Educational Facilities
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• v.23 no.3
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• pp.11-21
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• 2016

After the twenty-first century, the university emphasize on the role of knowledge creation facilities, and for this, various social and educational requirements are changing the environment of higher education. These change makes university that has old facilities difficult to correspond environmental changes. The purpose of this study is to review the facilities manual of Establishment and Management of university and to suggest amendment of Establishment and Management of university by exploring the university educational environment and facilities plan to respond various changes. We reviewed division of university studies, classification system of facilities, Area Standard of building and site in th provision for university establishment and operation, based on studying domestic university facilities standards, space management standards, facilities condition of national/private university and doing a survey of university facilities satisfaction and propriety of facilities standard in 120 universities. According to this study on validity and propriety of rules, we suggest amendment of Establishment and Management of university that can respond changing higher education environment.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.4
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• pp.45-51
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• 2021

A runway safety area (RSA) is defined as the surface surrounding the runway prepared or suitable for reducing the risk of damage to airplanes in the event of an undershoot, overshoot, or excursion from the runway. The Runway Stripe is a defined area including the runway stopway, if provided, intended firstly to reduce the risk of damage to aircraft running off a runway, and secondly, to protect aircraft flying over it during takeoff or landing operations. This study used 2 RSA analysis models; RSARA and LRSARA. The analysis utilizes historical data from the specific airport and allows to take into consideration specific operational conditions to which movements are subject, as well as the actual or planned RSA conditions in terms of dimensions, configuration, and boundaries defined by existing obstacles. This study applied the RSA and LRSA risk assessment models to a domestic airport that do not meet the criteria required by standards for aerodrome physical characteristics. The airport is considering a method to secure the runway strip standard through the displaced threshold. This study intends to confirm through quantitative risk estimation whether meeting facility standards through the runway displaced threshold leads to a positive change in risk mitigation.

• Journal of Information Technology Services
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• v.19 no.5
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• pp.33-47
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• 2020

In recent years, due to the demand for operating efficiency and cost reduction of industrial facilities, remote access via the Internet is expanding. the control network accelerates from network separation to network connection due to the development of IIoT (Industrial Internet of Things) technology. Transition of control network is a new opportunity, but concerns about cybersecurity are also growing. Therefore, manufacturers must reflect security compliance and standards in consideration of the Internet connection environment, and enterprises must newly recognize the connection area of the control network as a security management target. In this study, the core target of the control system security threat is defined as the network boundary, and issues regarding the security architecture configuration for the boundary and the role & responsibility of the working organization are covered. Enterprises do not integrate the design organization with the operation organization after go-live, and are not consistently reflecting security considerations from design to operation. At this point, the expansion of the control network is a big transition that calls for the establishment of a responsible organization and reinforcement of the role of the network boundary area where there is a concern about lack of management. Thus, through the organization of the facility network and the analysis of the roles between each organization, an static perspective and difference in perception were derived. In addition, standards and guidelines required for reinforcing network boundary security were studied to address essential operational standards that required the Internet connection of the control network. This study will help establish a network boundary management system that should be considered at the enterprise level in the future.

• Journal of Biosystems Engineering
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• v.40 no.1
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• pp.19-27
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• 2015

Purpose: A system to measure the visibility of agricultural tractor operators was designed and evaluated according to ISO standards, and a blind area diagram around the tested tractor was created based on the manual method recommended by the National Institute for Occupational Safety and Health (NIOSH). Methods: A visibility measurement system was designed and evaluated based on the ISO 5006 and ISO 5721-1 standards. Two bulbs used to simulate the operator's eyes were mounted on a bar with a supporting frame. A wooden frame was used to determine the seat index point position. The 12-m visibility test circle was divided into six sectors of vision, and the test tractor was placed at the center of the circle. Artificial light was supplied in the darkened environment, and shadow or masking effects were measured manually around the 12-m circle. Results: When the bulbs were placed at the operator's eye level, front visibility was good; no masking was found in the "A" vision sector, but larger masking widths were found in the "B" and "C" vision sectors. Since the masking width exceeded 700 mm, additional tests, such as movement of the light sources to both sides of the operator's eye level, were performed. Less than six masking effects were found in the semi-circle of vision to the front, and more than one masking was found in the "B" and "C" visual fields. The minimum distance between the centers of two masking effects exceeded 2500 mm when measured as a chord on the semi-circle of vision. A blind area diagram was created to define the exact nature of the blind spots and mirror visibility. Conclusions: Visibility evaluation is an effective way to enable proper and safe operation for agricultural tractor operators. Inclusion of this visibility evaluation test in the general testing process might aid tractor manufacturers.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.104-109
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• 2010

Lap joint friction stir welding(LFSW) is an relatively new solid state joining process. A6061-T6 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength to weight ratio and good corrosion resistance. Test methods used in this paper, lock-in thermography, a phase difference between the defect area and the healthy area indicates the qualitative location and size of the defect. In this paper, the defects detected from the thermal image of mechanical properties for weld were evaluated and compared by the lock-in infrared thermography technique.

• The Mathematical Education
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• v.62 no.4
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• pp.515-529
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• 2023

The purpose of this study is to analyze teachers' understanding of the number and operations area of grades 3 to 6 in elementary school mathematics curriculum and to derive implications for improving teachers' understanding of the mathematics curriculum. To this end, elementary school teachers were asked to develop items to evaluate curriculum achievement standards at each grade level, and then the teachers' understanding of the curriculum was examined based on the collected items. As a result of the study, there was a misinterpretation of the achievement standards in approximately 25% of the questions collected. Typically, cases where the content covered by each grade was confused when using textbooks as a standard, or cases where the difference between the content covered by the two achievement standards could not be completely distinguished were found.