• 한국멀티미디어학회논문지
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• 제10권12호
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• pp.1698-1703
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• 2007

The paper focuses on a new 'learning ecology' that is evolving and the challenges that educators must confront. It looks at e-learning as not just another add-on, but a technology that is transforming our educational institutions. How teaching and learning is conceptualized and experienced to generate a determined community of inquiry that integrates social, cognitive, and teaching presence in a manner that will take full advantage of the distinctive assets of e-learning is discussed. Likewise, the possibility of mobile learning is put forward.

• 수산해양기술연구
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• 제22권4호
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• pp.41-48
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• 1986

To investigate the midwater trawl gear available for the Korean near sea trawlers, the authors carried out a field experiment on the attitude and the opening efficiency of the otter board with the Pusan 404 (160GT, 750ps), a training ship of National Fisheries University of Pusan. The experimental trawl gear was designed to be operable by the ship and the otter board was made of single iron plate with 12% camber ratio. The special-prepared potentiometric angle detector was used for determining the attitude, and the 50 KHz fish finder for the opening between the otter boards. The results obtained can be summarized as follows: 1. The angle of attack varied by moving the towing point on the towing plate of the otter board. It showed 33 to 36 degrees when the point was set at the outmost position, 25 to 31 degrees at the middle position and 19 to 30 degrees at the inmost position, with a decreasing tendency according to the increase of towing speed in each cases. 2. The heel of the otter board always occured inwards, increasing slightly according to the increase of towing speed. 3. The tilt of the otter board always occured outwards, increasing slightly according to the move of the towing point inwards, and decreasing slightly according to the increase of towing speed. 4. The opening between otter boards showed the largest value when the towing point was set at the outmost position.

• Communications for Statistical Applications and Methods
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• 제21권4호
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• pp.285-296
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• 2014

The quantile residual life function has been effectively used to interpret results from the analysis of the proportional hazards model for censored survival data; however, the quantile residual life function is not always estimable with currently available semi-parametric regression methods in the presence of heavy censoring. A parametric regression approach may circumvent the difficulty of heavy censoring, but parametric assumptions on a baseline hazard function can cause a potential bias. This article proposes a Bayesian semi-parametric regression approach for inference on an unknown baseline hazard function while adjusting for available covariates. We consider a model-based approach but the proposed method does not suffer from strong parametric assumptions, enjoying a closed-form specification of the parametric regression approach without sacrificing the flexibility of the semi-parametric regression approach. The proposed method is applied to simulated data and heavily censored survival data to estimate various quantile residual lifetimes and adjust for important prognostic factors.

• 대한산업공학회지
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• 제34권3호
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• pp.318-327
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• 2008

This paper considers a single-machine scheduling problem with availability constraints. In many realistic situations, machines may not be always available due to various reasons such as maintenance, breakdown and repair. However, most literature on scheduling assume that the machines are available at all times. This paper deals with a single-machine scheduling problem with periodic maintenance. If the maintenance decision is made jointly with the job scheduling, the system will be more effective. The objective is to minimize the total completion time of jobs. This problem is proved to be NP-hard in the strong sense. The proposed breaking heuristic(BH) algorithm rule is established by some theorems and conditions. Our computational results show that the BH algorithm is much more efficient than existing heuristic.

• 한국철도학회논문집
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• 제14권2호
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• pp.87-93
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• 2011

본 연구는 Five-9's 가용도를 달성하기 위한 고가용도 시스템의 가용도 모델을 기술한다. 현대의 철도시스템은 지속적으로 서비스가 제공되어야 하는 고가용도 시스템으로 이러한 고가용도 서비스의 중요한 특성은 이동통신, 철도시스템, 정보운영 및 웹기반 사업 등 많은 현대의 사업에 필수적이며, 아키텍처 기반의 시스템 가용도 모델은 고가용도 목표의 만족여부를 평가하는 데 매우 유용하다. 마코브 모델 접근은 관련 시스템엔지니어가 시스템고장 및 고장복구 프로세스를 모델링할 때 직관적으로 적용가능하다. 본 연구는 UML2.0을 사용하여 개선된 가용도 모델을 제시하였다. 이러한 아키텍처기반의 시스템 가용도 모델은 철도시스템에 매우 의미있게 적용될 수 있다.

• International Journal of Computer Science & Network Security
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• 제22권7호
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• pp.21-28
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• 2022

The increase in the number of large cities and the size of their population sharpens attention to the new role of cities as entities to ensure a high-quality, safe and modern life of citizens, which has become significantly more active in recent years. The rapid spread of smart cities in the modern world has actualized the issue of analyzing their success and assessing the role of various factors in this. Every success of a smart city is always the result of a unique combination of the most modern technologies, environmental and social initiatives, skillful and consistent management, as well as available human potential. The purpose of the article is to analyze the success factors of smart cities based on the generalization of the results of the most famous ratings. In order to identify the impact of various factors, primarily intellectual, on the success and leadership positions of smart cities, the following ratings were consistently analyzed: Smart City Index (SCI), City in Motion Index (CIMI), Global Power City Index (GPCI), Global Cities Index (GCI), Global Cities Outlook (GCO). They have a different list of indicators and main pillars (dimensions), but all ratings take into account aspects such as: governance, ICT, mobility, functionality, human capital, etc. The highest correlation coefficient, that is, the strongest linear relationship of the CIMI index was found with such factors as: Human capital, Economy, Governance and Technologies. Summarizing the results of the TOP 20 smart cities according to different ratings allowed us to confirm that the list of leaders is very similar in all ratings. Among those cities that are in the TOP-20 in all five indexes are: London, Sydney and Singapore. There are four indices: New York, Paris, Tokyo, Copenhagen, Berlin, Amsterdam, Melbourne. Achieving leadership positions in smart city rankings is always the result of a combination and synergy of certain factors, and first of all, it is the quality of human capital. The intensity and success of the use of information and communication technologies in locality management processes, city planning and improvement of the city's living conditions depend on it.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.540-545
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• 2008

The design on balance shaft module is performed based on the target specification of engine module as well as the its own dynamic nature under a high speed rotation. However, the specific information for engine module is not always available for non-motor companies even though a reliable analytical result should be attached in the conceptual design process or more detail works. In this paper, the analysis on balance shaft module, both each parts or module itself, is suggested to estimate the performance on the target component with respect to durability and NVH without any consideration of a engine module. This methodology could modify the nominal balance shaft model before the production of prototype such that cost reduction as well as time saving can be expected during design process of balance shaft module.

• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.1013-1021
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• 2004

This paper presents the results of spectrum analysis of leakage current waveforms on contaminated polymer insulators under fog conditions. This is a basic study on development of a monitoring for aging degree and surface pollution state using distortion rate(%) of 3rd and 5th harmonics according fundamental frequency[60Hz] under environment conditions. Arcing on the surface was always associated with distortion in the leakage current ; hence the low frequency components of the leakage current can be used as a means to evaluate the surface degradation. The results indicate that the distortion rate by spectrum analysis is available for the monitoring of contamination condition of EPDM Polymer insulators.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.897-901
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• 2005

In the highway engineering, the performance, quantity and status of machines available for the project have direct impact on the project time. For instance, the status of machines, such as working or in trouble, have great influence on the activity execution. Therefore, while scheduling the project, the project manager always increases the spare machines or prolong the activity time to avoid delaying the project time when some of the machines are in trouble in construction site. However, how many are the spare machines and how long are the prolonged activity time, which are estimated subjectively by the manager. This subjective estimation has been criticized for systematically overestimating or underestimating quantity of the machines and the activity time. In the paper, we propose and prototype a model to simulate the status of the machines in construction site, and then to evaluate the schedule feasibility considering the performance, quantity and statues of the machines involved.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.47-51
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• 2013

Existing buildings now represent the greatest opportunity to improve building energy efficiency. Building performance analysis is becoming increasingly important because decision makers can have a better visualization of their building's performance and quickly make the solution for improving building energy efficiency and reducing environmental impacts. Nowadays, building information models (BIMs) have been widely created during the design phase of new buildings, and it can be easily imported to third party software to conduct various analyses. However, a BIM is not always available for all existing buildings. Even if a BIM is available during the design and construction phases, it is very challenging to keep updating it while a building is aged. A manual process to create or update a BIM is very time consuming and labor intensive. A laser scanning technology has been a popular tool to create as-is BIM. However it still needs labor-intensive manual processes to create a BIM out of point clouds. This paper introduces automatic as-is simplified BIM creation from point clouds for energy simulations. A framework of decision support system that can assist decision makers on retrofits for existing buildings is introduced as well. A case study on a residential house was tested in this study to validate the proposed framework, and the technical feasibility of the developed system was positively demonstrated.