• The Journal of Korean Association of Computer Education
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• v.12 no.5
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• pp.63-74
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• 2009

In this study, the contents of the revised curriculum in 2007 for the area of 'Information Society and Information Technology' in 'Informatics subject matter for middle school have been analyzed. In addition, evaluation standards have been suggested based on the achievement standards, which have been detailed according to the analyzed results in the study. Since the suggested achievement and evaluation standards have been developed based on the revision of the curriculum, the results in this study are expected to be helpful especially in 2010 for teaching and learning activities such as setting up the educational objects for teaching and learning, developing evaluation methods, improving the teaching and learning methods, setting the level and range of teaching and learning area, and etc.

• Journal of Power Electronics
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• v.15 no.1
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• pp.246-255
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• 2015

This paper presents experimental results and its assessment of a variable-speed wind power generation system (VSWPGS) using permanent magnet synchronous generator (PMSG) and boost chopper circuit (BCC). Experimental results are obtained by a test bench with a wind turbine emulator (WTE). WTE reproduces the behaviors of a windmill by using servo motor drives. The mechanical torque references to drive the servo motor are calculated from the windmill wing profile, wind velocity, and windmill rotational speed. VSWPGS using PMSG and BCC has three speed control modes for the level of wind velocity to control the rotational speed of the wind turbine. The control mode for low wind velocity regulates an armature current of generator with BCC. The control mode for middle wind velocity regulates a DC link voltage with a vector-controlled inverter. The control mode for high wind velocity regulates a pitch angle of the wind turbine with a pitch angle control system. The hybrid of three control modes extends the variable-speed range. BCC simplifies the maintenance of VSWPGS while improving reliability. In addition, VSWPGS using PMSG and BCC saves cost compared with VSWPGS using a PWM converter.

• Journal of the Korean Society of Safety
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• v.26 no.5
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• pp.99-104
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• 2011

An ILRT Interval for a nuclear power plant in Korea was extended from once in five years to once in ten years. Therefore, it is necessary to evaluate risk impact for ILRT interval extensions. In this paper, input data were generated for the reference plants, KSNP, using raw data such as meteorological data, population distribution data and source term data. And, using MACCS II code the risk impact assessment was performed based on the two methodologies of NUREG-1493 and NEI Interim Report. The risk impact derived from an ILRT interval extension was identified not to be significant. It is considered to apply this study and results to making an accident management plan and safety goal, and to the field of public acceptance.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.201-208
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• 2017

The major cause of the marine accidents is the collision with a moving object such as ship as well as the fixed object such as breakwater. Therefore, the most effective way to reduce the maritime ship accidents is the prevention of collision. In order to decrease the collision, it is principle that the navigation officer promptly judges the dangerous condition and makes the quick response. The ship does not allow any object or other ships approaching its surrounded area called ship area so that it prevents the collision. Generally, the ship which has high speed or poor maneuvering capability shall be managed from the distance so that the other ship does not invade its ship domains(watching distance, blocking distance). Accordingly, this study sets the navigational risk assessment model by applying ship dynamic domain and collision judgement method considered ship length, speed and navigational capability. It also reviewed the validity of the model and evaluated the perilous water way (Maenggol Channel) and a curved route near Maenggol Channel. As a result, in case of a ship with 100m in length passing Maenggol Channel, it represented "warning" level before 1.5nm to the entry, "dangerous"level 0.75nm before to it and "very dangerous" level 0.5nm before to it and then "dangerous"level again up to the entry. Applying to the curved route also showed the same results as the Narrow Channel or Maenggol Channel. This analysis highly matched with the actual navigation results. In the future, this model will be useful for coastal navigation safety chart development and safety evaluation for route or port development. It also allows to evaluate the dangerous route or the best route by applying the result into ECDIS so that it will finally help to reduce the marine accidents. Eventually the model will be effective for the marine traffic simulation evaluation forced by Maritime Traffic Safety Act.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.16-18
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• 2011

This study aims to identify the degree of safety when mariners take their actions in several different situations. We have carried out many experiments in order to observe mariners' behavior, and then measured the safety level that is based on their actions to avoid dangerous collision situations. One of the most important actions that mariners have to take, either as their daily routine or when they are in a collision situation and then want to avoid that situation is the lookout. In this paper, behaviors on the lookout have been defined as a standard sequence of three steps that are "time of first detection", "time of recognition as risky vessel" and "time of starting avoiding action", and the suitability and applicability of the definition have been shown. And also we propose the risk assessment on the collision and the recommendation for reducing the collision at sea. Some analyzing results and the application of the results are reported. The sequence of lookout is also understood. By combining these knowledge and some systematic studies, we propose the risk assessment on the collision and the recommendation for reducing the collision at sea.

• Journal of Auto-vehicle Safety Association
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• v.12 no.3
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• pp.43-51
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• 2020

Currently, the second level of the six stages of self-driving technology, as defined by SAE, is commercialized, and the third level is preparing for commercialization. The purpose of ACC is to be evaluated as a system useful for preventing and preventing accidents by minimizing driver fatigue through longitudinal speed control and relative distance control of the vehicle. In this regard, for the study of safety assessment methods in the practical environment of ACC. Distance measurement method using monocular camera and data acquisition equipment such as DGPS are utilized. Based on the evaluation scenario considering the domestic road environment proposed by the preceding study, the relative distance obtained from equipment such as DPGS and the relative distance using a monocular camera in the actual test is verified by comparing and analyzing the safety assessment. The comparison by scenario results showed a minimum error rate of 3.83% in Scenario 1 and a maximum of 14.61% in Scenario 6. The cause of the maximum error is that the lane recognition is not accurate in the camera image and irregular operation conditions such as rushing in or exiting the surrounding area from the walkway. It is expected that safety evaluation using a monocular camera will be possible for other ADAS systems in the future.

• Nuclear Engineering and Technology
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• v.25 no.3
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• pp.447-456
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• 1993

A simplified model to assess the performance of engineered barrier for the retardation of radionuclide release in a low- and intermediate-level radioactive waste repository was developed. The model is based on the repository design concept being suggested in Korea, and considers two types of release scenario ; a design-bas release for the design of engineered barrier and a realistic release for the performance assessment. For the numerical illustration, the sample calculations were performed for five radionuclides with different chemical characteristics, and the results were analyzed.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.435-439
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• 2015

It is important for Singaporean companies to manage the multifaceted risks when forming international construction joint ventures (ICJVs) with developing countries. The objectives of this study are to assess the risks associated with Singaporean ICJVs with developing countries, and investigate the risk allocation preferences in these ICJVs. To fulfill these objectives, a literature review was carried out and a questionnaire survey was performed with 38 professionals. The survey results reported "political instability" as the most critical risk, and market level risks were less critical than country and project level risks. Additionally, the results showed agreement on the risk ranking between building and infrastructure ICJVs, despite significant differences in the criticalities of five risks. Furthermore, five risks were preferably allocated to host and foreign partners, respectively, while 13 risks could be shared among partners. As few studies have explored the risk allocation preferences in ICJVs, this study expands the literature. Also, the identification of the risks allows other companies to customize their own lists of critical risks, while the preferred risk allocation provides valuable information for companies from various countries that intend to form ICJVs with developing countries. Thus, this study contributes to the global body of knowledge relating to ICJVs.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.127-136
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• 2024

Because the hazardous working environments and high labor intensity of the root industry can potentially impact the health of workers, current regulations have focused on measuring and controlling environmental factors, on a semi-annual basis. However, there is a lack of quantitative criteria addressing workers' health conditions other than the physical work environment. This gap makes it challenging to prevent occupational diseases resulting from continuous exposure to harmful substances below regulatory thresholds. Therefore, this paper proposes a machine learning-based method for determining the peak level of risk in root industry work environments and enables real-time safety assessment in workplaces utilizing this approach.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.423-434
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• 2016

The importance of severe nuclear accidents and probabilistic safety assessment (PSA) were brought to international attention with the occurrence of severe nuclear accidents caused by the extreme natural disaster at Fukushima Daiichi nuclear power plant in Japan. In Korea, studies on level 3 PSA had made little progress until recently. The code systems of level 3 PSA, MACCS2 (MELCORE Accident Consequence Code System 2, US), COSYMA (COde SYstem from MAria, EU) and OSCAAR (Off-Site Consequence Analysis code for Atmospheric Releases in reactor accidents, JAPAN), were reviewed in this study, and the disadvantages and limitations of MACCS2 were also analyzed. Experts from Korea and abroad pointed out that the limitations of MACCS2 include the following: MACCS2 cannot simulate multi-unit accidents/release from spent fuel pools, and its atmospheric dispersion is based on a simple Gaussian plume model. Some of these limitations have been improved in the updated versions of MACCS2. The absence of a marine and aquatic dispersion model and the limited simulating range of food-chain and economic models are also important aspects that need to be improved. This paper is expected to be utilized as basic research material for developing a Korean code system for assessing off-site consequences of severe nuclear accidents.