• 동력기계공학회지
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• 제22권1호
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• pp.41-47
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• 2018

This paper analyzes the output characteristics of a self excited induction generator with isolated mode according to change of its speeds and loads for building a hybrid electric propulsion system in special purpose ships by using power take off. The induction generators are being considered as an alternative choice to the well-developed generators because of their lower unit cost, inherent ruggedness, operational and maintenance simplicity. However, the generator working by stand alone has a few problems that the reactive power is required to establish the air gap magnetic flux, and the induced voltage and magnetizing current fluctuate when the load is varied. In spite of its advantages, basic design data of the capacitor bank and behaviors of the output characteristics of the generator are not sufficient for the system. Based on the operating condition(speed range of main engine) of the target boat, a reduced experimental equipment system was constructed to analyze the output characteristics of the SEIG. And a suitable capacitor bank of a stand-alone generator and its output characteristics under various loads was investigated in detail through these experiments. According to the experimental result, it was confirmed that the capacitor bank should be $70{\mu}F{\sim}100{\mu}F$, and the proper SEIG induced voltage should be DC 80 V ~ 250 V in order to storage electrical energy into a battery.

• 산업경영시스템학회지
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• 제41권2호
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• pp.153-158
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• 2018

At the Bank of Korea, capital stock statistics were created by the PIM (perpetual inventory method) with fixed capital formation data. Asset classifications also included 2 categories in residential buildings, 4 non-residential buildings, 14 constructions, 9 transportation equipment, 28 machinery, and 2 intangible fixed assets. It is the Korean government accounting system which is developed much with the field of the national accounts including the valuation, but until 2008 it was consistent with single-entry bookkeeping. Many countries, including Korea, were single-entry bookkeeping, not double-entry bookkeeping which can be aggregated by government accounting standard account. There was no distinction in journaling between revenue and capital expenditure when it was consistent with single-entry bookkeeping. For example, we would like to appropriately divide the past budget accounts and the settlement accounts data that have been spent on dredging into capital expenditure and revenue expenditure. It, then, tries to add the capital expenditure calculated to FCF (fixed capital formation), because revenue expenditure is cost for maintenance etc. This could be a new direction, especially, in the estimation of capital stock by the perpetual inventory method for infrastructure (SOC, social overhead capital). It should also be noted that there are differences not only between capital and income expenditure but also by other factors. How long will this difference be covered by the difference between the 'new series' and 'old series' methodologies? In addition, there is no large difference between two series by the major asset classification level. If this is treated as a round-off error, this is a problem.

• 대한지역사회영양학회지
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• 제8권5호
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• pp.744-754
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• 2003

At present, health care industries throughout the world are struggling with the challenges to set up financial structures as cost-effective ways and means of satisfying customer needs for health care services. Many hospitals consign foodservice management to foodservice companies for the purpose of efficiency. The companies taking charge of hospital foodservice are also striving to gain an advantage over keen competitions. This study applied Quality Function Deployment(QFD) to one hospital (which will be shown as $\ulcorner$A hospital$\lrcorner$ below) managed by a contract foodservice company for the purpose of strategy planning to provide sustainable competitive advantage. First of all, this study scanned internal and external environment of $\ulcorner$A hospital$\lrcorner$ by means of a Quality Measurement Tool and a fieldwork study. With the result of environment scanning, this study elicited 20 strategies through SWOT analysis, which were categorized by 4 perspectives such as financial, customer, internal process, learning and growth perspectives. Finally, the priorities of 20 strategies were extracted from QFD methodology. According to the results obtained by applying QFD to $\ulcorner$A hospital$\lrcorner$'s foodservice, the strategies which $\ulcorner$A hospital$\lrcorner$ foodservice was obliged to introduce and implement were : the specialization of Children's hospital foodservice, scientific foodservice management through the standardization of foodservice operations, the maintenance of sanitary quality through sanitary system, the remodeling of facilities, the introduction of new equipment, the prompt and accurate response to customer needs, the development of appropriate patient menus, the provision of competitively priced meals for patient selection, the development of a demand forecast model by considering the characteristics of a children's hospital, improvement of productivity and the reduction of labor costs through the employment of experienced employees based on their seniority.

• 전력전자학회논문지
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• 제8권6호
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• pp.478-487
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• 2003

본 논문에서는 고압 대용량 전동기 구동용 멀티레벨 인버터의 종류 및 특징을 간략히 살펴보고, 특히 입출력 전력품질이 우수하고 전압별 시리즈화가 용이한 H-브릿지 멀티레벨 인버터의 구조적 특징 및 장점을 기술하였다. 연구 개발된 3,300V lMVA 용량의 Cascaded H-브릿지 멀티레벨 인버터의 구체적인 전력회로 구조 및 설계방법, 제어기 구성 그리고 PWM 기법을 제시하였다. 또한, 실용량의 시험을 통해 H-브릿지 멀티레벨 인버터는 출력 전압 Step이 여러 단계이고 dv/dt가 적으며 입력단 THD를 크게 낮출 수 있어 성능 면에서도 여타 방식보다 우수함을 입증하였다. 또한 생산적인 측면에서도 저압 소자를 사용하여 설계하므로 기존의 생산/시험 기술과 설비를 이용할 수 있어 매우 경제적이며 Power Cell 단위 결합 구조이므로 신뢰성 측면이나 보수/유지 측면에서도 유리하다는 결론을 얻었다.

• 전기학회논문지
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• 제62권2호
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• pp.257-263
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• 2013

In case of image observation equipments, CCTV for short distance visual field is usually installed and operated mostly as the means of crime-prevention. However, the extensive demand for monitoring problems in case of the increase in intelligent crimes and disasters has led to the necessity of the development of long-distance observation equipments embedded with Night View functions. In case of the Night View equipments, the relevant market is set up to be focused mostly on Thermal Observation Device(hereinafter, TOD), but some shortcomings such as the limitation of image visibility and excessive maintenance cost, etc. have actually caused the necessity of new long distance Night View equipment. Moreover there might follow lots of difficulties in long-distance visualization in the event that irregular reflection is generated by minute particles in the atmosphere such as fog, smog, and dust, etc. These factors are motivate the work presented in this study. Our study is aimed at the realization of Pulsed Laser Illuminator and newly proposed Range-Gated image acquisition technology. And also the implementation of Tracker for continuous trace of the objects of interest from the obtained sequence images.

• 한국지능시스템학회논문지
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• 제19권5호
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• pp.699-705
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• 2009

본 논문은 지게차 AGV(autonomous ground vehicle)의 자율주행을 위한 제어 방법에 관한 연구이다. 기존에 개발된 지게차 AGV의 위치측정 방법으로는 자기-자이로 유도(magnet-gyro guidance) 방식과 유선 유도(wire guidance) 방법이 있지만, 유지보수에 대한 지속적인 노력과 비용문제가 있으며, 작업 환경의 변화에 따라 작업 환경을 재구성해야하는 단점이 있다. 따라서 본 논문에서는 외란에 강인하고 작업 환경 및 작업 내용의 변경에 유연한 시스템을 구축하기 위해 레이저 내비게이션 센서와 엔코더, 자이로 센서의 센서융합을 통한 위치측정 시스템을 개발하였다. 또한 팔레트를 하역 운송해야하는 지게차 AGV의 주행제어를 위해 팔레트와 지게차 AGV 사이의 거리 차와 각도 차를 바탕으로 퍼지 제어 및 비례 제어를 이용한 주행제어기를 설계하였다. 본 연구에서 제안한 지게차 AGV를 위한 제어 시스템의 성능 분석을 위해 물류 운송작업이 가능한 작업공간에서 동일한 하역 작업을 10회 반복 하였다. 그 결과, 시뮬레이션에 의해 생성된 경로와 실제 주행경로의 최대 평균 오차가 87.77mm를 가짐을 확인하였다.

• 한국전자통신학회논문지
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• 제14권1호
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• pp.155-160
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• 2019

본 논문에서는 신재생에너지와 농업ICT를 활용한 시설농업용 제어와 에너지생산량과 소비량 예측을 통해 효율적인 계통 독립형 ESS제어시스템을 제안한다. 제안된 시스템은 전력계통 정밀 위상 및 데이터를 시각화하여 유지보수 및 모니터링을 수행할 수 있는 통합 관리 시스템으로 장애 발생 시 자동으로 이에 대해 대처하고 데이터 수집, 처리, 제어가 가능하며, 태양광발전의 전력 발전과 설치된 설비들의 소비 패턴, 설비들의 동작 트랜드를 분석, 기상청 OpenAPI를 활용한 에너지 생산량 소비량 예측을 통해 최적의 에너지 운영 방법을 제시함으로써 불필요한 에너지 소비를 줄이고 운영비용을 절감할 수 있다.

• International journal of advanced smart convergence
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• 제12권3호
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• pp.1-12
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• 2023

A public address (PA) system installed in a building is a system that delivers alerts, announcements, instructions, etc. in an emergency or disaster situation. As for the products used in PA systems, with the development of information and communication technology, PA products with various functions have been introduced to the market. PA systems recently launched in the market may be connected through a single network to enable efficient management and operation, or use voice recognition technology to deliver quick information in case of an emergency. In addition, a system capable of locating a user inside a building using a location-based service and guiding or responding to a safe area in the event of an emergency is being launched on the market. However, the new PA systems currently on the market add some functions to the existing PA system configuration to make system operation more convenient, but they do not change the complex PA system configuration to reduce facility costs, maintenance, and management costs. In this paper, we propose a novel PA system configuration for buildings using audio networks and control hierarchy over peer-to-peer (Anchor) technology based on audio over IP (AoIP), which simplifies the complex PA system configuration and enables convenient operation and management. As a result of the study, through the emergency signal processing algorithm, fire broadcasting was made possible according to the detection of the existence of a fire signal in the Anchor system. In addition, the control device of the PA system was replaced with software to reduce the equipment installation cost, and the PA system configuration was simplified. In the future, it is expected that the PA system using Anchor technology will become the standard for PA facilities.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제30권3호
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• pp.45-56
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• 2024

Purpose: It is important to note that the relative importance of risk factors should be identified to successfully complete the remodeling project of general hospital. Approached by analytic hierarchy process (AHP), the present study aimed to systematically evaluate the risk factors for remodeling of general hospital. Methods: The present work classified the risk factors of general hospital remodeling into four major categories including the requirements survey stage, planning and design stage, dismantling and construction stage, and maintenance stage. In addition, four sub-categories were derived from each major category factor. Furthermore, five major categories and four subcategories were selected to be considered from the perspectives of two stakeholders of contractor and constructor. The relative importance of the major and sub-categories factors was calculated using the AHP technique on the survey data collected from 49 respondents who participated in the survey study. Results: The results indicate that, the risk factor of requirements survey stage was found to be the most important risk factor to consider among the four major categories of factors. Also, insufficient preliminary investigation, design inconsistencies in architecture/mechanics/electricity, occurrence of safety accidents, and insufficient review of various equipment capacities and performances were found to have the highest priorities of each subcategory factor group included in the four major categories. From the perspective of contractor, the error in predicting the construction period was found to be the most important risk factor. The occurrence of safety accidents during construction was found to be the most important risk factor to be considered by constructor. Implications: The result of the current work should provide important insights and guidelines for the risk management activity that contributes to controlling the project time, cost, and scope required for general hospital remodeling.

• 한국구조물진단유지관리공학회 논문집
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• 제21권5호
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• pp.49-55
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• 2017

1970년대에 여러 연구자가 시제품 시험장비를 가지고 인발시험을 실시하였으며, 인발시험은 콘크리트 강도를 결정하는 신뢰할 만한 비파괴검사 방법(NDT)으로 입증되었다. 우리는 고강도 콘크리트 강도를 추정하기 위하여 직경 10 mm볼트에 홈이 파인 파단형 인발 볼트와 인발너트, 그리고 로드셀이 필요 없는 오일 유압펌프를 포함한 간이 인발시험법을 제안하였다. 저비용, 간편성 및 편의성을 갖는 간이인발시험의 이점을 검증하기 위하여, 30 MPa 및 50 MPa 급 두가지 유형의 콘크리트로 제작된 4개의 모의벽체를 대상으로 로드셀을 장착한 간이인발시험을 사용하여 인발시험을 실시하였다. 인발하중과 콘크리트 압축강도는 재령 7일까지는 매일, 그리고 14일, 21일, 28일에 측정되었다. 시험결과 인발하중과 콘크리트 압축강도는 매우 밀접한 상관관계를 보여주었으며 따라서 인발하중이 현장에서 구조물의 고강도 콘크리트 강도를 평가할 수 있다는 것을 확인할 수 있었다. 파단형 인발볼트 직경과 콘크리트 강도와의 관계식으로 y=0.05x+3.79(x=콘크리트 압축강도, y=파단형 인발볼트 직경)이 도출되었으며 결정계수는 0.88로 나타났다.