• 한국콘텐츠학회논문지
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• 제13권2호
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• pp.32-43
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• 2013

최근 많은 기관들로부터 클라우드 서비스가 향후 대세적인 IT서비스로의 확고한 기술로서 예견하고 있고, 실질적으로 IT를 리딩하는 많은 벤더 기업들을 주축으로 실질적인 클라우드 서비스를 제공 하고 있다. 따라서 클라우드 사용자는 서비스의 물리적인 위치나, 시스템 환경과 같은 부분들을 관여하지 않고, 스토리지 서비스, 데이터의 사용, 소프트웨어의 사용들을 제공하는 획기적인 서비스로 거듭나고 있다. 한편, 클라우드 컴퓨팅 기술들은 인프라스트럭처에서 요구되는 서비스의 수준, 다양한 시스템에서 요구되는 하드웨어적인 문제들을 벗어서 자유스럽게 원하는 만큼의 IT 리소스를 쉽게 사용할 수 있는 장점을 가지고 있지만, 고가용성 측면에서 반드시 기술적인 해결 방안을 모색하여야 한다. 따라서 본 논문 에서는 고가용성 측면에서의 클라우드 컴퓨팅을 위해 분산 파일 시스템이 갖추어야 할 사항들과 클라우드 컴퓨팅에서 활용 가능한 오픈소스 기반의 하둡 분산 파일 시스템, 메모리 데이터베이스 기술, 고가용성 데이터베이스 시스템을 소개하고 현재 클라우드 컴퓨팅 시장에서 활용되고 있는 분산 파일 시스템을 통한 분산처리 기술을 참고하여 고가용성 대용량 분산 데이터 처리 아키텍처를 클라우드 서비스 측면에서 구현하였다.

• 한국철도학회논문집
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• 제16권3호
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• pp.163-168
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• 2013

장기간 수명주기(Life Cycle)을 갖는 도시철도차량은 초기 도입비용보다 유지보수비용이 많은 비중(60%~70%)을 점유하고 있으므로 효율적인 유지보수 연구를 통하여 유지보수 비용의 절감과 대형시스템의 수명연장을 추구하는 일이 무엇보다 시급하다. 이를 위해 신뢰성기반의 유지보수체계에 대해 여러 산업분야의 국내 외 사례 조사 분석을 통해 도시철도차량 신뢰도/가용도 관리시스템을 구성하였다. 본 연구에서는 이 시스템이 가져야 할 주요 기능을 상세히 정하고 성공적인 시스템 개발이 될 수 있도록 관련 시스템을 개발하였다. 본 논문은 성공적으로 개발이 완료된 도시철도차량 신뢰도/가용도 관리시스템에 관한 내용을 기술한 것이다.

• 터널과지하공간
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• 제32권4호
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• pp.254-271
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• 2022

본 연구에서는 GMG (Global Mining Guidelines Group)에서 제안한 시간 사용 모델과 핵심성과지표(KPIs)들을 이용하여 트럭 운반작업에 대한 성과를 평가한 결과를 제시하였다. 이를 위해 철과 티탄 철을 주로 생산하는 국내 지하광산을 연구지역으로 선정한 다음 블루투스 비콘과 태블릿 PC를 이용하여 트럭 운반작업 데이터를 수집하였다. 수집된 데이터를 분석하여 트럭 운반작업의 단위작업, 활동 및 이벤트, 소요시간을 식별하였으며, 시간 사용 모델을 기반으로 시간 범주를 분류하였다. 트럭 운반작업의 성과는 가용률, 이용률, 효율성 측면의 9개 성과지표를 이용하여 평가하였다. 그 결과, 가용률 측면에서는 가동시간이 33.9%, 물리적 가용률은 95.7%, 기계적 가용률은 94.9%로 나타났다. 이용률의 경우, 가용장비 이용률은 83.1%, 자산 이용률은 28.1%, 운영 및 유효 이용률은 각각 79.6%, 77.7%로 나타났다. 또한, 효율성 측면에서는 운영 효율성이 97.6%로 높게 나타났으며, 생산 효율성은 49%로 나타났다.

• 한국의류학회지
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• 제35권9호
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• pp.1099-1111
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• 2011

This study identified the types of consumer review information about apparel products based on consumer satisfaction/dissatisfaction with the availability/non-availability of consumer review information for online stores. Data were collected from 318 females aged 20s' to 30s', who had significant experience in reading consumer reviews posted on online stores. Consumer satisfaction/dissatisfaction with availability or non-availability of review information on online stores is different for information in regards to apparel product attributes, product benefits, and store attributes. According to the concept of quality elements suggested by the Kano model, two types of consumer review information were determined: Must-have information (product attribute information about size, fabric, color and design of the apparel product; benefit information about washing & care and comport of the apparel product; store attribute information about responsiveness, disclosure, delivery and after service of the store) and attracting information (attribute information about price comparison; benefit information about coordination with other items, fashionability, price discounts, value for price, reaction from others, emotion experienced during transaction, symbolic features for status, health functionality, and eco-friendly feature; store attribute information about return/refund, damage compensation and reputation/credibility of online store and interactive and dynamic nature of reviews among customers). There were significant differences between the high and low involvement groups in their perceptions of consumer review information.

• 대한가정학회지
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• 제50권1호
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• pp.103-119
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• 2012

The purpose of this study was to explore the mediating effects of preschooler's effortful control on the relationship between maternal emotional availability and preschooler's social skills and problem behaviors. One hundred-thirty six 5-year-old preschoolers and their mothers participated in this study. Instruments for this study were the Emotional Availability Scale for maternal emotional availability, the Delay task, and the Child Behavior Questionnaire for preschooler's effortful control, and the Social Skill Rating Scale, K-CBCL 1.5-5 and K-TRF for preschooler's social skills and problem behaviors. The resulting data were analyzed using descriptive statistics, partial correlation, and structural equation modeling analysis. As predicted, the preschooler's effortful control mediated the effects of maternal emotional availability on preschooler's social skills and problem behaviors. In conclusion, the preschooler's effortful control mediates the effects of emotion related socialization behavior on the preschooler's socio-emotional adjustment.

• Journal of the Korean Data and Information Science Society
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• 제19권2호
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• pp.645-655
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• 2008

As wireless connectivity is integrated into many handheld devices, streaming multimedia content among mobile ad-hoc peers is becoming a popular application. In this paper, we propose a dynamic service replication algorithm for providing guaranteed continuous streaming services to all nodes in mobile ad-hoc networks (MANETs). First, a MANET is comprised of logical grid hierarchy, and a streaming service is replicated to a lower server region of the logical grid hierarchy by considering the link availability between a mobile node and the streaming server within a server region or the popularity of the streaming service. We evaluate analytically the performance of the proposed algorithm, and compared with that of existing Qin's algorithm. Evaluation results show that our algorithm can achieve better streaming performance than Qin's algorithm. Therefore, the proposed algorithm not only improves the sharing availability of replicated streaming services but also controls efficiently the number of streaming service replications.

• 한국군사과학기술학회지
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• 제23권2호
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• pp.168-175
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• 2020

Failure of essential avionic equipments have a significant impact on the operations and safety of P-3 maritime patrol aircraft. Therefore, avionic equipments of P-3 are required to have higher reliability. Based on the field failure data, this paper studies the reliability growth of essential avionic equipments in P-3 using Duane model. Additionally, a simulation model is built and implemented for identifying the operational availability according to the field failure data of avionic equipments.

• 한국컴퓨터정보학회논문지
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• 제22권12호
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• pp.179-186
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• 2017

Managing students' data is a high prioritized duty of the university administration since most of the school affairs are proceed based on that database. Universities have invested in IT assets such as servers, storage, database, and networks. However, continuing investment in IT infrastructure is impossible due to limited budget and rapid changes in the educational environment. As cloud computing diffuse, universities are trying to reduce costs and improve efficiency by increasing server utilization, unlike when physically investing. We designed a hypothetical academic information management system based on cloud computing by utilizing the advanced server virtualization technology. This administrative cloud system allows universities to improve the availability of the system with low cost. The system demonstrates its flexibility of using data resources and immediacy of resumption.

• 한국군사과학기술학회지
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• 제13권1호
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• pp.41-49
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• 2010

In this paper, we propose a hierarchical RAM simulation model framework which are used to analyze the RAM specifications on the concept refinement phase. The hierarchical RAM simulation model framework consists of RAM simulation models, class library and each model's input and output data lists. The hierarchical RAM simulation models are co-operated with 3 kinds of model - type I, II, III. Type I, II models are used to analyze the target operational availability and Type III is used to establish the initial RAM specifications. Each model's input and output data lists are defined by considering each model's purpose of RAM analysis. The class library is arranged with each model's classes for implementing the hierarchical simulation models. The proposed framework may be applied for executing the RAM activities effectively.

• Communications for Statistical Applications and Methods
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• 제29권2호
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• pp.151-160
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• 2022

The total system is composed of the main system (MS) and the failure detection equipment (FDE) which detects failures of MS. The analysis of system reliability is performed when the failure of FDE is possible. Several repair policies are considered to determine the order of repair of failed systems, which are sequential repair (SQ), priority repair (PR), independent repair (ID), and simultaneous repair (SM). The states of MS-FDE systems are represented by Markov models according to repair policies and the main purpose of this paper is to derive the system availabilities of the Markov models. Analytical solutions of the stationary equations are derived for the Markov models and the system availabilities are immediately determined using the stationary solutions. A simple illustrative example is discussed for the comparison of availability values of the repair policies considered in this paper.